Rearrange flutter assemble implementation (#36240)

packages/flutter_tools/lib/src/build_system/build_system.dart

@@ -18,30 +18,9 @@ import '../globals.dart';
 import 'exceptions.dart';
 import 'file_hash_store.dart';
 import 'source.dart';
-import 'targets/assets.dart';
-import 'targets/dart.dart';
-import 'targets/ios.dart';
-import 'targets/linux.dart';
-import 'targets/macos.dart';
-import 'targets/windows.dart';
 
 export 'source.dart';
 
-/// The function signature of a build target which can be invoked to perform
-/// the underlying task.
-typedef BuildAction = FutureOr<void> Function(
-    Map<String, ChangeType> inputs, Environment environment);
-
-/// A description of the update to each input file.
-enum ChangeType {
-  /// The file was added.
-  Added,
-  /// The file was deleted.
-  Removed,
-  /// The file was modified.
-  Modified,
-}
-
 /// Configuration for the build system itself.
 class BuildSystemConfig {
   /// Create a new [BuildSystemConfig].
@@ -102,7 +81,7 @@ class BuildSystemConfig {
 /// Example: aot_elf has a dependency on the dill and packages file
 /// produced by the kernel_snapshot step.
 ///
-/// ### Targest should declare all outputs produced
+/// ### Targets should declare all outputs produced
 ///
 /// If a target produces an output it should be listed, even if it is not
 /// intended to be consumed by another target.
@@ -116,43 +95,38 @@ class BuildSystemConfig {
 /// exercise the rule, ensuring that the existing input and output verification
 /// logic can run, as well as verifying it correctly handles provided defines
 /// and meets any additional contracts present in the target.
-class Target {
+abstract class Target {
-  const Target({
+  const Target();
-    @required this.name,
-    @required this.inputs,
-    @required this.outputs,
-    @required this.buildAction,
-    this.dependencies = const <Target>[],
-  });
-
   /// The user-readable name of the target.
   ///
   /// This information is surfaced in the assemble commands and used as an
   /// argument to build a particular target.
-  final String name;
+  String get name;
 
   /// The dependencies of this target.
-  final List<Target> dependencies;
+  List<Target> get dependencies;
 
   /// The input [Source]s which are diffed to determine if a target should run.
-  final List<Source> inputs;
+  List<Source> get inputs;
 
   /// The output [Source]s which we attempt to verify are correctly produced.
-  final List<Source> outputs;
+  List<Source> get outputs;
 
   /// The action which performs this build step.
-  final BuildAction buildAction;
+  Future<void> build(List<File> inputFiles, Environment environment);
 
   /// Collect hashes for all inputs to determine if any have changed.
-  Future<Map<String, ChangeType>> computeChanges(
+  ///
+  /// Returns whether this target can be skipped.
+  Future<bool> computeChanges(
     List<File> inputs,
     Environment environment,
     FileHashStore fileHashStore,
   ) async {
-    final Map<String, ChangeType> updates = <String, ChangeType>{};
     final File stamp = _findStampFile(environment);
     final Set<String> previousInputs = <String>{};
     final List<String> previousOutputs = <String>[];
+    bool canSkip = true;
 
     // If the stamp file doesn't exist, we haven't run this step before and
     // all inputs were added.
@@ -161,6 +135,8 @@ class Target {
       // Something went wrong writing the stamp file.
       if (content == null || content.isEmpty) {
         stamp.deleteSync();
+        // Malformed stamp file, not safe to skip.
+        canSkip = false;
       } else {
         final Map<String, Object> values = json.decode(content);
         final List<Object> inputs = values['inputs'];
@@ -168,12 +144,13 @@ class Target {
         inputs.cast<String>().forEach(previousInputs.add);
         outputs.cast<String>().forEach(previousOutputs.add);
       }
+    } else {
+      // No stamp file, not safe to skip.
+      canSkip = false;
     }
 
-    // For each input type, first determine if we've already computed the hash
+    // For each input, first determine if we've already computed the hash
-    // for it. If not and it is a directory we skip hashing and instead use a
+    // for it. Then collect it to be sent off for hashing as a group.
-    // timestamp. If it is a file we collect it to be sent off for hashing as
-    // a group.
     final List<File> sourcesToHash = <File>[];
     final List<File> missingInputs = <File>[];
     for (File file in inputs) {
@@ -187,19 +164,19 @@ class Target {
       if (fileHashStore.currentHashes.containsKey(absolutePath)) {
         final String currentHash = fileHashStore.currentHashes[absolutePath];
         if (currentHash != previousHash) {
-          updates[absolutePath] = previousInputs.contains(absolutePath)
+          canSkip = false;
-              ? ChangeType.Modified
-              : ChangeType.Added;
         }
       } else {
         sourcesToHash.add(file);
       }
     }
-    // Check if any outputs were deleted or modified from the previous run.
+
+    // For each outut, first determine if we've already computed the hash
+    // for it. Then collect it to be sent off for hashing as a group.
     for (String previousOutput in previousOutputs) {
       final File file = fs.file(previousOutput);
       if (!file.existsSync()) {
-        updates[previousOutput] = ChangeType.Removed;
+        canSkip = false;
         continue;
       }
       final String absolutePath = file.resolveSymbolicLinksSync();
@@ -207,15 +184,14 @@ class Target {
       if (fileHashStore.currentHashes.containsKey(absolutePath)) {
         final String currentHash = fileHashStore.currentHashes[absolutePath];
         if (currentHash != previousHash) {
-          updates[absolutePath] = previousInputs.contains(absolutePath)
+          canSkip = false;
-              ? ChangeType.Modified
-              : ChangeType.Added;
         }
       } else {
         sourcesToHash.add(file);
       }
     }
 
+    // If we depend on a file that doesnt exist on disk, kill the build.
     if (missingInputs.isNotEmpty) {
       throw MissingInputException(missingInputs, name);
     }
@@ -224,24 +200,11 @@ class Target {
     // update the result.
     if (sourcesToHash.isNotEmpty) {
       final List<File> dirty = await fileHashStore.hashFiles(sourcesToHash);
-      for (File file in dirty) {
+      if (dirty.isNotEmpty) {
-        final String absolutePath = file.resolveSymbolicLinksSync();
+        canSkip = false;
-        updates[absolutePath] = previousInputs.contains(absolutePath)
-            ? ChangeType.Modified
-            : ChangeType.Added;
       }
     }
-
+    return canSkip;
-    // Find which, if any, inputs have been deleted.
-    final Set<String> currentInputPaths = Set<String>.from(
-      inputs.map<String>((File entity) => entity.resolveSymbolicLinksSync())
-    );
-    for (String previousInput in previousInputs) {
-      if (!currentInputPaths.contains(previousInput)) {
-        updates[previousInput] = ChangeType.Removed;
-      }
-    }
-    return updates;
   }
 
   /// Invoke to remove the stamp file if the [buildAction] threw an exception;
@@ -413,6 +376,7 @@ class Environment {
       rootBuildDir: rootBuildDir,
       cacheDir: Cache.instance.getRoot(),
       defines: defines,
+      flutterRootDir: fs.directory(Cache.flutterRoot),
     );
   }
 
@@ -422,6 +386,7 @@ class Environment {
     @required this.rootBuildDir,
     @required this.cacheDir,
     @required this.defines,
+    @required this.flutterRootDir,
   });
 
   /// The [Source] value which is substituted with the path to [projectDir].
@@ -454,6 +419,11 @@ class Environment {
   /// the flutter tool.
   final Directory cacheDir;
 
+  /// The `FLUTTER_ROOT` environment variable.
+  ///
+  /// Defaults to to the value of [Cache.flutterRoot].
+  final Directory flutterRootDir;
+
   /// Additional configuration passed to the build targets.
   ///
   /// Setting values here forces a unique build directory to be chosen
@@ -477,36 +447,14 @@ class BuildResult {
 
 /// The build system is responsible for invoking and ordering [Target]s.
 class BuildSystem {
-  BuildSystem([Map<String, Target> targets])
+  const BuildSystem();
-    : targets = targets ?? _defaultTargets;
 
-  /// All currently registered targets.
+  /// Build `target` and all of its dependencies.
-  static final Map<String, Target> _defaultTargets = <String, Target>{
-    unpackMacos.name: unpackMacos,
-    macosApplication.name: macosApplication,
-    macoReleaseApplication.name: macoReleaseApplication,
-    unpackLinux.name: unpackLinux,
-    unpackWindows.name: unpackWindows,
-    copyAssets.name: copyAssets,
-    kernelSnapshot.name: kernelSnapshot,
-    aotElfProfile.name: aotElfProfile,
-    aotElfRelease.name: aotElfRelease,
-    aotAssemblyProfile.name: aotAssemblyProfile,
-    aotAssemblyRelease.name: aotAssemblyRelease,
-    releaseIosApplication.name: releaseIosApplication,
-    profileIosApplication.name: profileIosApplication,
-    debugIosApplication.name: debugIosApplication,
-  };
-
-  final Map<String, Target> targets;
-
-  /// Build the target `name` and all of its dependencies.
   Future<BuildResult> build(
-    String name,
+    Target target,
     Environment environment,
-    BuildSystemConfig buildSystemConfig,
+    { BuildSystemConfig buildSystemConfig = const BuildSystemConfig() }
   ) async {
-    final Target target = _getNamedTarget(name);
     environment.buildDir.createSync(recursive: true);
 
     // Load file hash store from previous builds.
@@ -530,35 +478,6 @@ class BuildSystem {
       buildInstance.stepTimings,
     );
   }
-
-  /// Describe the target `name` and all of its dependencies.
-  List<Map<String, Object>> describe(
-    String name,
-    Environment environment,
-  ) {
-    final Target target = _getNamedTarget(name);
-    environment.buildDir.createSync(recursive: true);
-    checkCycles(target);
-    // Cheat a bit and re-use the same map.
-    Map<String, Map<String, Object>> fold(Map<String, Map<String, Object>> accumulation, Target current) {
-      accumulation[current.name] = current.toJson(environment);
-      return accumulation;
-    }
-
-    final Map<String, Map<String, Object>> result =
-        <String, Map<String, Object>>{};
-    final Map<String, Map<String, Object>> targets = target.fold(result, fold);
-    return targets.values.toList();
-  }
-
-  // Returns the corresponding target or throws.
-  Target _getNamedTarget(String name) {
-    final Target target = targets[name];
-    if (target == null) {
-      throw Exception('No registered target:$name.');
-    }
-    return target;
-  }
 }
 
 /// An active instance of a build.
@@ -594,14 +513,13 @@ class _BuildInstance {
     bool skipped = false;
     try {
       final List<File> inputs = target.resolveInputs(environment);
-      final Map<String, ChangeType> updates = await target.computeChanges(inputs, environment, fileCache);
+      final bool canSkip = await target.computeChanges(inputs, environment, fileCache);
-      if (updates.isEmpty) {
+      if (canSkip) {
         skipped = true;
         printStatus('Skipping target: ${target.name}');
       } else {
         printStatus('${target.name}: Starting');
-        // build actions may be null.
+        await target.build(inputs, environment);
-        await target?.buildAction(updates, environment);
         printStatus('${target.name}: Complete');
 
         final List<File> outputs = target.resolveOutputs(environment);
@@ -610,7 +528,6 @@ class _BuildInstance {
         target._writeStamp(inputs, outputs, environment);
       }
     } catch (exception, stackTrace) {
-      // TODO(jonahwilliams): test
       target.clearStamp(environment);
       passed = false;
       skipped = false;

packages/flutter_tools/lib/src/build_system/source.dart

@@ -65,8 +65,9 @@ class SourceVisitor {
             fs.path.split(environment.cacheDir.resolveSymbolicLinksSync()));
         break;
       case Environment.kFlutterRootDirectory:
+        // flutter root will not contain a symbolic link.
         segments.addAll(
-            fs.path.split(environment.cacheDir.resolveSymbolicLinksSync()));
+            fs.path.split(environment.flutterRootDir.absolute.path));
         break;
       default:
         throw InvalidPatternException(pattern);

packages/flutter_tools/lib/src/build_system/targets/assets.dart

@@ -10,10 +10,6 @@ import '../../devfs.dart';
 import '../build_system.dart';
 
 /// The copying logic for flutter assets.
-// TODO(jonahwilliams): combine the asset bundle logic with this rule so that
-// we can compute the key for deleted assets. This is required to remove assets
-// from build directories that are no longer part of the manifest and to unify
-// the update/diff logic.
 class AssetBehavior extends SourceBehavior {
   const AssetBehavior();
 
@@ -24,6 +20,8 @@ class AssetBehavior extends SourceBehavior {
       manifestPath: environment.projectDir.childFile('pubspec.yaml').path,
       packagesPath: environment.projectDir.childFile('.packages').path,
     );
+    // Filter the file type to remove the files that are generated by this
+    // command as inputs.
     final List<File> results = <File>[];
     final Iterable<DevFSFileContent> files = assetBundle.entries.values.whereType<DevFSFileContent>();
     for (DevFSFileContent devFsContent in files) {
@@ -40,56 +38,65 @@ class AssetBehavior extends SourceBehavior {
       packagesPath: environment.projectDir.childFile('.packages').path,
     );
     final List<File> results = <File>[];
-    for (MapEntry<String, DevFSContent> entry in assetBundle.entries.entries) {
+    for (String key in assetBundle.entries.keys) {
-      final File file = fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', entry.key));
+      final File file = fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', key));
       results.add(file);
     }
     return results;
   }
 }
 
-/// Copies the asset files from the [copyAssets] rule into place.
+/// Copy the assets defined in the flutter manifest into a build directory.
-Future<void> copyAssetsInvocation(Map<String, ChangeType> updates, Environment environment) async {
+class CopyAssets extends Target {
-  final Directory output = environment
+  const CopyAssets();
-    .buildDir
-    .childDirectory('flutter_assets');
-  if (output.existsSync()) {
-    output.deleteSync(recursive: true);
-  }
-  output.createSync(recursive: true);
-  final AssetBundle assetBundle = AssetBundleFactory.instance.createBundle();
-  await assetBundle.build(
-    manifestPath: environment.projectDir.childFile('pubspec.yaml').path,
-    packagesPath: environment.projectDir.childFile('.packages').path,
-  );
-  // Limit number of open files to avoid running out of file descriptors.
-  final Pool pool = Pool(64);
-  await Future.wait<void>(
-    assetBundle.entries.entries.map<Future<void>>((MapEntry<String, DevFSContent> entry) async {
-      final PoolResource resource = await pool.request();
-      try {
-        final File file = fs.file(fs.path.join(output.path, entry.key));
-        file.parent.createSync(recursive: true);
-        await file.writeAsBytes(await entry.value.contentsAsBytes());
-      } finally {
-        resource.release();
-      }
-    }));
-}
 
-/// Copy the assets used in the application into a build directory.
+  @override
-const Target copyAssets = Target(
+  String get name => 'copy_assets';
-  name: 'copy_assets',
+
-  inputs: <Source>[
+  @override
+  List<Target> get dependencies => const <Target>[];
+
+  @override
+  List<Source> get inputs => const <Source>[
+    Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/assets.dart'),
     Source.pattern('{PROJECT_DIR}/pubspec.yaml'),
     Source.behavior(AssetBehavior()),
-  ],
+  ];
-  outputs: <Source>[
+
+  @override
+  List<Source> get outputs => const <Source>[
     Source.pattern('{BUILD_DIR}/flutter_assets/AssetManifest.json'),
     Source.pattern('{BUILD_DIR}/flutter_assets/FontManifest.json'),
     Source.pattern('{BUILD_DIR}/flutter_assets/LICENSE'),
     Source.behavior(AssetBehavior()), // <- everything in this subdirectory.
-  ],
+  ];
-  dependencies: <Target>[],
+
-  buildAction: copyAssetsInvocation,
+  @override
-);
+  Future<void> build(List<File> inputFiles, Environment environment) async {
+    final Directory output = environment
+      .buildDir
+      .childDirectory('flutter_assets');
+    if (output.existsSync()) {
+      output.deleteSync(recursive: true);
+    }
+    output.createSync(recursive: true);
+    final AssetBundle assetBundle = AssetBundleFactory.instance.createBundle();
+    await assetBundle.build(
+      manifestPath: environment.projectDir.childFile('pubspec.yaml').path,
+      packagesPath: environment.projectDir.childFile('.packages').path,
+    );
+    // Limit number of open files to avoid running out of file descriptors.
+    final Pool pool = Pool(64);
+    await Future.wait<void>(
+      assetBundle.entries.entries.map<Future<void>>((MapEntry<String, DevFSContent> entry) async {
+        final PoolResource resource = await pool.request();
+        try {
+          final File file = fs.file(fs.path.join(output.path, entry.key));
+          file.parent.createSync(recursive: true);
+          await file.writeAsBytes(await entry.value.contentsAsBytes());
+        } finally {
+          resource.release();
+        }
+      }));
+  }
+}

packages/flutter_tools/lib/src/build_system/targets/dart.dart

@@ -5,9 +5,7 @@
 import '../../artifacts.dart';
 import '../../base/build.dart';
 import '../../base/file_system.dart';
-import '../../base/io.dart';
 import '../../base/platform.dart';
-import '../../base/process_manager.dart';
 import '../../build_info.dart';
 import '../../compile.dart';
 import '../../dart/package_map.dart';
@@ -36,63 +34,6 @@ const String kBitcodeFlag = 'EnableBitcode';
 /// The other supported value is armv7, the 32-bit iOS architecture.
 const String kIosArchs = 'IosArchs';
 
-/// Supports compiling dart source to kernel with a subset of flags.
-///
-/// This is a non-incremental compile so the specific [updates] are ignored.
-Future<void> compileKernel(Map<String, ChangeType> updates, Environment environment) async {
-  final KernelCompiler compiler = await kernelCompilerFactory.create(
-    FlutterProject.fromDirectory(environment.projectDir),
-  );
-  if (environment.defines[kBuildMode] == null) {
-    throw MissingDefineException(kBuildMode, 'kernel_snapshot');
-  }
-  final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
-  final String targetFile = environment.defines[kTargetFile] ?? fs.path.join('lib', 'main.dart');
-
-  final CompilerOutput output = await compiler.compile(
-    sdkRoot: artifacts.getArtifactPath(Artifact.flutterPatchedSdkPath, mode: buildMode),
-    aot: buildMode != BuildMode.debug,
-    trackWidgetCreation: false,
-    targetModel: TargetModel.flutter,
-    targetProductVm: buildMode == BuildMode.release,
-    outputFilePath: environment
-      .buildDir
-      .childFile('main.app.dill')
-      .path,
-    depFilePath: null,
-    mainPath: targetFile,
-  );
-  if (output.errorCount != 0) {
-    throw Exception('Errors during snapshot creation: $output');
-  }
-}
-
-/// Supports compiling a dart kernel file to an ELF binary.
-Future<void> compileAotElf(Map<String, ChangeType> updates, Environment environment) async {
-  final AOTSnapshotter snapshotter = AOTSnapshotter(reportTimings: false);
-  final String outputPath = environment.buildDir.path;
-  if (environment.defines[kBuildMode] == null) {
-    throw MissingDefineException(kBuildMode, 'aot_elf');
-  }
-  if (environment.defines[kTargetPlatform] == null) {
-    throw MissingDefineException(kTargetPlatform, 'aot_elf');
-  }
-
-  final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
-  final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);
-  final int snapshotExitCode = await snapshotter.build(
-    platform: targetPlatform,
-    buildMode: buildMode,
-    mainPath: environment.buildDir.childFile('main.app.dill').path,
-    packagesPath: environment.projectDir.childFile('.packages').path,
-    outputPath: outputPath,
-    bitcode: false,
-  );
-  if (snapshotExitCode != 0) {
-    throw Exception('AOT snapshotter exited with code $snapshotExitCode');
-  }
-}
-
 /// Finds the locations of all dart files within the project.
 ///
 /// This does not attempt to determine if a file is used or imported, so it
@@ -111,96 +52,99 @@ List<File> listDartSources(Environment environment) {
   return dartFiles;
 }
 
-/// Supports compiling a dart kernel file to an assembly file.
-///
-/// If more than one iOS arch is provided, then this rule will
-/// produce a univeral binary.
-Future<void> compileAotAssembly(Map<String, ChangeType> updates, Environment environment) async {
-  final AOTSnapshotter snapshotter = AOTSnapshotter(reportTimings: false);
-  final String outputPath = environment.buildDir.path;
-  if (environment.defines[kBuildMode] == null) {
-    throw MissingDefineException(kBuildMode, 'aot_assembly');
-  }
-  if (environment.defines[kTargetPlatform] == null) {
-    throw MissingDefineException(kTargetPlatform, 'aot_assembly');
-  }
-  final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
-  final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);
-  final List<IOSArch> iosArchs = environment.defines[kIosArchs]?.split(',')?.map(getIOSArchForName)?.toList()
-      ?? <IOSArch>[IOSArch.arm64];
-  if (targetPlatform != TargetPlatform.ios) {
-    throw Exception('aot_assembly is only supported for iOS applications');
-  }
-  final bool bitcode = environment.defines[kBitcodeFlag] == 'true';
-
-  // If we're building for a single architecture (common), then skip the lipo.
-  if (iosArchs.length == 1) {
-    final int snapshotExitCode = await snapshotter.build(
-      platform: targetPlatform,
-      buildMode: buildMode,
-      mainPath: environment.buildDir.childFile('main.app.dill').path,
-      packagesPath: environment.projectDir.childFile('.packages').path,
-      outputPath: outputPath,
-      iosArch: iosArchs.single,
-      bitcode: bitcode,
-    );
-    if (snapshotExitCode != 0) {
-      throw Exception('AOT snapshotter exited with code $snapshotExitCode');
-    }
-  } else {
-    // If we're building multiple iOS archs the binaries need to be lipo'd
-    // together.
-    final List<Future<int>> pending = <Future<int>>[];
-    for (IOSArch iosArch in iosArchs) {
-      pending.add(snapshotter.build(
-        platform: targetPlatform,
-        buildMode: buildMode,
-        mainPath: environment.buildDir.childFile('main.app.dill').path,
-        packagesPath: environment.projectDir.childFile('.packages').path,
-        outputPath: fs.path.join(outputPath, getNameForIOSArch(iosArch)),
-        iosArch: iosArch,
-        bitcode: bitcode,
-      ));
-    }
-    final List<int> results = await Future.wait(pending);
-    if (results.any((int result) => result != 0)) {
-      throw Exception('AOT snapshotter exited with code ${results.join()}');
-    }
-    final ProcessResult result = await processManager.run(<String>[
-      'lipo',
-      ...iosArchs.map((IOSArch iosArch) =>
-          fs.path.join(outputPath, getNameForIOSArch(iosArch), 'App.framework', 'App')),
-      '-create',
-      '-output',
-      fs.path.join(outputPath, 'App.framework', 'App'),
-    ]);
-    if (result.exitCode != 0) {
-      throw Exception('lipo exited with code ${result.exitCode}');
-    }
-  }
-}
-
 /// Generate a snapshot of the dart code used in the program.
-const Target kernelSnapshot = Target(
+class KernelSnapshot extends Target {
-  name: 'kernel_snapshot',
+  const KernelSnapshot();
-  inputs: <Source>[
+
+  @override
+  String get name => 'kernel_snapshot';
+
+  @override
+  List<Source> get inputs => const <Source>[
+    Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/dart.dart'),
     Source.function(listDartSources), // <- every dart file under {PROJECT_DIR}/lib and in .packages
     Source.artifact(Artifact.platformKernelDill),
     Source.artifact(Artifact.engineDartBinary),
     Source.artifact(Artifact.frontendServerSnapshotForEngineDartSdk),
-  ],
+  ];
-  outputs: <Source>[
+
-    Source.pattern('{BUILD_DIR}/main.app.dill'),
+  @override
-  ],
+  List<Source> get outputs => const <Source>[
-  dependencies: <Target>[],
+    Source.pattern('{BUILD_DIR}/app.dill'),
-  buildAction: compileKernel,
+  ];
-);
+
+  @override
+  List<Target> get dependencies => <Target>[];
+
+  @override
+  Future<void> build(List<File> inputFiles, Environment environment) async {
+    final KernelCompiler compiler = await kernelCompilerFactory.create(
+      FlutterProject.fromDirectory(environment.projectDir),
+    );
+    if (environment.defines[kBuildMode] == null) {
+      throw MissingDefineException(kBuildMode, 'kernel_snapshot');
+    }
+    final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
+    final String targetFile = environment.defines[kTargetFile] ?? fs.path.join('lib', 'main.dart');
+
+    final CompilerOutput output = await compiler.compile(
+      sdkRoot: artifacts.getArtifactPath(Artifact.flutterPatchedSdkPath, mode: buildMode),
+      aot: buildMode != BuildMode.debug,
+      trackWidgetCreation: false,
+      targetModel: TargetModel.flutter,
+      targetProductVm: buildMode == BuildMode.release,
+      outputFilePath: environment.buildDir.childFile('app.dill').path,
+      depFilePath: null,
+      mainPath: targetFile,
+    );
+    if (output.errorCount != 0) {
+      throw Exception('Errors during snapshot creation: $output');
+    }
+  }
+}
+
+
+/// Supports compiling a dart kernel file to an ELF binary.
+abstract class AotElfBase extends Target {
+  const AotElfBase();
+
+  @override
+  Future<void> build(List<File> inputFiles, Environment environment) async {
+    final AOTSnapshotter snapshotter = AOTSnapshotter(reportTimings: false);
+    final String outputPath = environment.buildDir.path;
+    if (environment.defines[kBuildMode] == null) {
+      throw MissingDefineException(kBuildMode, 'aot_elf');
+    }
+    if (environment.defines[kTargetPlatform] == null) {
+      throw MissingDefineException(kTargetPlatform, 'aot_elf');
+    }
+    final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
+    final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);
+    final int snapshotExitCode = await snapshotter.build(
+      platform: targetPlatform,
+      buildMode: buildMode,
+      mainPath: environment.buildDir.childFile('app.dill').path,
+      packagesPath: environment.projectDir.childFile('.packages').path,
+      outputPath: outputPath,
+      bitcode: false,
+    );
+    if (snapshotExitCode != 0) {
+      throw Exception('AOT snapshotter exited with code $snapshotExitCode');
+    }
+  }
+}
 
 /// Generate an ELF binary from a dart kernel file in profile mode.
-const Target aotElfProfile = Target(
+class AotElfProfile extends AotElfBase {
-  name: 'aot_elf_profile',
+  const AotElfProfile();
-  inputs: <Source>[
+
-    Source.pattern('{BUILD_DIR}/main.app.dill'),
+  @override
+  String get name => 'aot_elf_profile';
+
+  @override
+  List<Source> get inputs => const <Source>[
+    Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/dart.dart'),
+    Source.pattern('{BUILD_DIR}/app.dill'),
     Source.pattern('{PROJECT_DIR}/.packages'),
     Source.artifact(Artifact.engineDartBinary),
     Source.artifact(Artifact.skyEnginePath),
@@ -208,21 +152,30 @@ const Target aotElfProfile = Target(
       platform: TargetPlatform.android_arm,
       mode: BuildMode.profile,
     ),
-  ],
+  ];
-  outputs: <Source>[
+
+  @override
+  List<Source> get outputs => const <Source>[
     Source.pattern('{BUILD_DIR}/app.so'),
-  ],
+  ];
-  dependencies: <Target>[
+
-    kernelSnapshot,
+  @override
-  ],
+  List<Target> get dependencies => const <Target>[
-  buildAction: compileAotElf,
+    KernelSnapshot(),
-);
+  ];
+}
 
 /// Generate an ELF binary from a dart kernel file in release mode.
-const Target aotElfRelease= Target(
+class AotElfRelease extends AotElfBase {
-  name: 'aot_elf_release',
+  const AotElfRelease();
-  inputs: <Source>[
+
-    Source.pattern('{BUILD_DIR}/main.app.dill'),
+  @override
+  String get name => 'aot_elf_release';
+
+  @override
+  List<Source> get inputs => const <Source>[
+    Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/dart.dart'),
+    Source.pattern('{BUILD_DIR}/app.dill'),
     Source.pattern('{PROJECT_DIR}/.packages'),
     Source.artifact(Artifact.engineDartBinary),
     Source.artifact(Artifact.skyEnginePath),
@@ -230,62 +183,15 @@ const Target aotElfRelease= Target(
       platform: TargetPlatform.android_arm,
       mode: BuildMode.release,
     ),
-  ],
+  ];
-  outputs: <Source>[
+
+  @override
+  List<Source> get outputs => const <Source>[
     Source.pattern('{BUILD_DIR}/app.so'),
-  ],
+  ];
-  dependencies: <Target>[
-    kernelSnapshot,
-  ],
-  buildAction: compileAotElf,
-);
 
-/// Generate an assembly target from a dart kernel file in profile mode.
+  @override
-const Target aotAssemblyProfile = Target(
+  List<Target> get dependencies => const <Target>[
-  name: 'aot_assembly_profile',
+    KernelSnapshot(),
-  inputs: <Source>[
+  ];
-    Source.pattern('{BUILD_DIR}/main.app.dill'),
+}
-    Source.pattern('{PROJECT_DIR}/.packages'),
-    Source.artifact(Artifact.engineDartBinary),
-    Source.artifact(Artifact.skyEnginePath),
-    Source.artifact(Artifact.genSnapshot,
-      platform: TargetPlatform.ios,
-      mode: BuildMode.profile,
-    ),
-  ],
-  outputs: <Source>[
-    // TODO(jonahwilliams): are these used or just a side effect?
-    // Source.pattern('{BUILD_DIR}/snapshot_assembly.S'),
-    // Source.pattern('{BUILD_DIR}/snapshot_assembly.o'),
-    Source.pattern('{BUILD_DIR}/App.framework/App'),
-  ],
-  dependencies: <Target>[
-    kernelSnapshot,
-  ],
-  buildAction: compileAotAssembly,
-);
-
-/// Generate an assembly target from a dart kernel file in release mode.
-const Target aotAssemblyRelease = Target(
-  name: 'aot_assembly_release',
-  inputs: <Source>[
-    Source.pattern('{BUILD_DIR}/main.app.dill'),
-    Source.pattern('{PROJECT_DIR}/.packages'),
-    Source.artifact(Artifact.engineDartBinary),
-    Source.artifact(Artifact.skyEnginePath),
-    Source.artifact(Artifact.genSnapshot,
-      platform: TargetPlatform.ios,
-      mode: BuildMode.release,
-    ),
-  ],
-  outputs: <Source>[
-    // TODO(jonahwilliams): are these used or just a side effect?
-    // Source.pattern('{BUILD_DIR}/snapshot_assembly.S'),
-    // Source.pattern('{BUILD_DIR}/snapshot_assembly.o'),
-    Source.pattern('{BUILD_DIR}/App.framework/App'),
-  ],
-  dependencies: <Target>[
-    kernelSnapshot,
-  ],
-  buildAction: compileAotAssembly,
-);

packages/flutter_tools/lib/src/build_system/targets/ios.dart

@@ -2,42 +2,149 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import '../../artifacts.dart';
+import '../../base/build.dart';
+import '../../base/file_system.dart';
+import '../../base/io.dart';
+import '../../base/process_manager.dart';
+import '../../build_info.dart';
 import '../build_system.dart';
-import 'assets.dart';
+import '../exceptions.dart';
 import 'dart.dart';
 
-/// Create an iOS debug application.
+/// Supports compiling a dart kernel file to an assembly file.
-const Target debugIosApplication = Target(
+///
-  name: 'debug_ios_application',
+/// If more than one iOS arch is provided, then this rule will
-  buildAction: null,
+/// produce a univeral binary.
-  inputs: <Source>[],
+abstract class AotAssemblyBase extends Target {
-  outputs: <Source>[],
+  const AotAssemblyBase();
-  dependencies: <Target>[
-    copyAssets,
-    kernelSnapshot,
-  ]
-);
 
-/// Create an iOS profile application.
+  @override
-const Target profileIosApplication = Target(
+  Future<void> build(List<File> inputFiles, Environment environment) async {
-  name: 'profile_ios_application',
+    final AOTSnapshotter snapshotter = AOTSnapshotter(reportTimings: false);
-  buildAction: null,
+    final String outputPath = environment.buildDir.path;
-  inputs: <Source>[],
+    if (environment.defines[kBuildMode] == null) {
-  outputs: <Source>[],
+      throw MissingDefineException(kBuildMode, 'aot_assembly');
-  dependencies: <Target>[
+    }
-    copyAssets,
+    if (environment.defines[kTargetPlatform] == null) {
-    aotAssemblyProfile,
+      throw MissingDefineException(kTargetPlatform, 'aot_assembly');
-  ]
+    }
-);
+    final bool bitcode = environment.defines[kBitcodeFlag] == 'true';
+    final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
+    final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);
+    final List<IOSArch> iosArchs = environment.defines[kIosArchs]?.split(',')?.map(getIOSArchForName)?.toList()
+        ?? <IOSArch>[IOSArch.arm64];
+    if (targetPlatform != TargetPlatform.ios) {
+      throw Exception('aot_assembly is only supported for iOS applications');
+    }
 
-/// Create an iOS debug application.
+    // If we're building for a single architecture (common), then skip the lipo.
-const Target releaseIosApplication = Target(
+    if (iosArchs.length == 1) {
-  name: 'release_ios_application',
+      final int snapshotExitCode = await snapshotter.build(
-  buildAction: null,
+        platform: targetPlatform,
-  inputs: <Source>[],
+        buildMode: buildMode,
-  outputs: <Source>[],
+        mainPath: environment.buildDir.childFile('app.dill').path,
-  dependencies: <Target>[
+        packagesPath: environment.projectDir.childFile('.packages').path,
-    copyAssets,
+        outputPath: outputPath,
-    aotAssemblyRelease,
+        iosArch: iosArchs.single,
-  ]
+        bitcode: bitcode,
-);
+      );
+      if (snapshotExitCode != 0) {
+        throw Exception('AOT snapshotter exited with code $snapshotExitCode');
+      }
+    } else {
+      // If we're building multiple iOS archs the binaries need to be lipo'd
+      // together.
+      final List<Future<int>> pending = <Future<int>>[];
+      for (IOSArch iosArch in iosArchs) {
+        pending.add(snapshotter.build(
+          platform: targetPlatform,
+          buildMode: buildMode,
+          mainPath: environment.buildDir.childFile('app.dill').path,
+          packagesPath: environment.projectDir.childFile('.packages').path,
+          outputPath: fs.path.join(outputPath, getNameForIOSArch(iosArch)),
+          iosArch: iosArch,
+          bitcode: bitcode,
+        ));
+      }
+      final List<int> results = await Future.wait(pending);
+      if (results.any((int result) => result != 0)) {
+        throw Exception('AOT snapshotter exited with code ${results.join()}');
+      }
+      final ProcessResult result = await processManager.run(<String>[
+        'lipo',
+        ...iosArchs.map((IOSArch iosArch) =>
+            fs.path.join(outputPath, getNameForIOSArch(iosArch), 'App.framework', 'App')),
+        '-create',
+        '-output',
+        fs.path.join(outputPath, 'App.framework', 'App'),
+      ]);
+      if (result.exitCode != 0) {
+        throw Exception('lipo exited with code ${result.exitCode}');
+      }
+    }
+  }
+}
+
+/// Generate an assembly target from a dart kernel file in release mode.
+class AotAssemblyRelease extends AotAssemblyBase {
+  const AotAssemblyRelease();
+
+  @override
+  String get name => 'aot_assembly_release';
+
+  @override
+  List<Source> get inputs => const <Source>[
+    Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/ios.dart'),
+    Source.pattern('{BUILD_DIR}/app.dill'),
+    Source.pattern('{PROJECT_DIR}/.packages'),
+    Source.artifact(Artifact.engineDartBinary),
+    Source.artifact(Artifact.skyEnginePath),
+    Source.artifact(Artifact.genSnapshot,
+      platform: TargetPlatform.ios,
+      mode: BuildMode.release,
+    ),
+  ];
+
+  @override
+  List<Source> get outputs => const <Source>[
+    Source.pattern('{BUILD_DIR}/App.framework/App'),
+  ];
+
+  @override
+  List<Target> get dependencies => const <Target>[
+    KernelSnapshot(),
+  ];
+}
+
+
+/// Generate an assembly target from a dart kernel file in profile mode.
+class AotAssemblyProfile extends AotAssemblyBase {
+  const AotAssemblyProfile();
+
+  @override
+  String get name => 'aot_assembly_profile';
+
+  @override
+  List<Source> get inputs => const <Source>[
+    Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/ios.dart'),
+    Source.pattern('{BUILD_DIR}/app.dill'),
+    Source.pattern('{PROJECT_DIR}/.packages'),
+    Source.artifact(Artifact.engineDartBinary),
+    Source.artifact(Artifact.skyEnginePath),
+    Source.artifact(Artifact.genSnapshot,
+      platform: TargetPlatform.ios,
+      mode: BuildMode.profile,
+    ),
+  ];
+
+  @override
+  List<Source> get outputs => const <Source>[
+    Source.pattern('{BUILD_DIR}/App.framework/App'),
+  ];
+
+  @override
+  List<Target> get dependencies => const <Target>[
+    KernelSnapshot(),
+  ];
+}

packages/flutter_tools/lib/src/build_system/targets/linux.dart

@@ -7,32 +7,21 @@ import '../../base/file_system.dart';
 import '../../globals.dart';
 import '../build_system.dart';
 
-// Copies all of the input files to the correct copy dir.
-Future<void> copyLinuxAssets(Map<String, ChangeType> updates,
-    Environment environment) async {
-  final String basePath = artifacts.getArtifactPath(Artifact.linuxDesktopPath);
-  for (String input in updates.keys) {
-    final String outputPath = fs.path.join(
-      environment.projectDir.path,
-      'linux',
-      'flutter',
-      fs.path.relative(input, from: basePath),
-    );
-    final File destinationFile = fs.file(outputPath);
-    if (!destinationFile.parent.existsSync()) {
-      destinationFile.parent.createSync(recursive: true);
-    }
-    fs.file(input).copySync(destinationFile.path);
-  }
-}
-
 /// Copies the Linux desktop embedding files to the copy directory.
-const Target unpackLinux = Target(
+class UnpackLinux extends Target {
-  name: 'unpack_linux',
+  const UnpackLinux();
-  inputs: <Source>[
+
+  @override
+  String get name => 'unpack_linux';
+
+  @override
+  List<Source> get inputs => const <Source>[
+    Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/linux.dart'),
     Source.artifact(Artifact.linuxDesktopPath),
-  ],
+  ];
-  outputs: <Source>[
+
+  @override
+  List<Source> get outputs => const <Source>[
     Source.pattern('{PROJECT_DIR}/linux/flutter/libflutter_linux.so'),
     Source.pattern('{PROJECT_DIR}/linux/flutter/flutter_export.h'),
     Source.pattern('{PROJECT_DIR}/linux/flutter/flutter_messenger.h'),
@@ -40,7 +29,29 @@ const Target unpackLinux = Target(
     Source.pattern('{PROJECT_DIR}/linux/flutter/flutter_glfw.h'),
     Source.pattern('{PROJECT_DIR}/linux/flutter/icudtl.dat'),
     Source.pattern('{PROJECT_DIR}/linux/flutter/cpp_client_wrapper/*'),
-  ],
+  ];
-  dependencies: <Target>[],
+
-  buildAction: copyLinuxAssets,
+  @override
-);
+  List<Target> get dependencies => <Target>[];
+
+  @override
+  Future<void> build(List<File> inputFiles, Environment environment) async {
+    final String basePath = artifacts.getArtifactPath(Artifact.linuxDesktopPath);
+    for (File input in inputFiles) {
+      if (fs.path.basename(input.path) == 'linux.dart') {
+        continue;
+      }
+      final String outputPath = fs.path.join(
+        environment.projectDir.path,
+        'linux',
+        'flutter',
+        fs.path.relative(input.path, from: basePath),
+      );
+      final File destinationFile = fs.file(outputPath);
+      if (!destinationFile.parent.existsSync()) {
+        destinationFile.parent.createSync(recursive: true);
+      }
+      fs.file(input).copySync(destinationFile.path);
+    }
+  }
+}

packages/flutter_tools/lib/src/build_system/targets/macos.dart

@@ -8,8 +8,8 @@ import '../../base/io.dart';
 import '../../base/process_manager.dart';
 import '../../globals.dart';
 import '../build_system.dart';
-import 'assets.dart';
+
-import 'dart.dart';
+const String _kOutputPrefix = '{PROJECT_DIR}/macos/Flutter/FlutterMacOS.framework';
 
 /// Copy the macOS framework to the correct copy dir by invoking 'cp -R'.
 ///
@@ -19,37 +19,20 @@ import 'dart.dart';
 /// Removes any previous version of the framework that already exists in the
 /// target directory.
 // TODO(jonahwilliams): remove shell out.
-Future<void> copyFramework(Map<String, ChangeType> updates,
+class UnpackMacOS extends Target {
-    Environment environment) async {
+  const UnpackMacOS();
-  final String basePath = artifacts.getArtifactPath(Artifact.flutterMacOSFramework);
-  final Directory targetDirectory = environment
-    .projectDir
-    .childDirectory('macos')
-    .childDirectory('Flutter')
-    .childDirectory('FlutterMacOS.framework');
-  if (targetDirectory.existsSync()) {
-    targetDirectory.deleteSync(recursive: true);
-  }
 
-  final ProcessResult result = processManager
+  @override
-      .runSync(<String>['cp', '-R', basePath, targetDirectory.path]);
+  String get name => 'unpack_macos';
-  if (result.exitCode != 0) {
-    throw Exception(
-      'Failed to copy framework (exit ${result.exitCode}:\n'
-      '${result.stdout}\n---\n${result.stderr}',
-    );
-  }
-}
 
-const String _kOutputPrefix = '{PROJECT_DIR}/macos/Flutter/FlutterMacOS.framework';
+  @override
-
+  List<Source> get inputs => const <Source>[
-/// Copies the macOS desktop framework to the copy directory.
+    Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/macos.dart'),
-const Target unpackMacos = Target(
-  name: 'unpack_macos',
-  inputs: <Source>[
     Source.artifact(Artifact.flutterMacOSFramework),
-  ],
+  ];
-  outputs: <Source>[
+
+  @override
+  List<Source> get outputs => const <Source>[
     Source.pattern('$_kOutputPrefix/FlutterMacOS'),
     // Headers
     Source.pattern('$_kOutputPrefix/Headers/FLEOpenGLContextHandling.h'),
@@ -68,33 +51,30 @@ const Target unpackMacos = Target(
     Source.pattern('$_kOutputPrefix/Resources/icudtl.dat'),
     Source.pattern('$_kOutputPrefix/Resources/info.plist'),
     // Ignore Versions folder for now
-  ],
+  ];
-  dependencies: <Target>[],
-  buildAction: copyFramework,
-);
 
-/// Build a macOS application.
+  @override
-const Target macosApplication = Target(
+  List<Target> get dependencies => <Target>[];
-  name: 'debug_macos_application',
-  buildAction: null,
-  inputs: <Source>[],
-  outputs: <Source>[],
-  dependencies: <Target>[
-    unpackMacos,
-    kernelSnapshot,
-    copyAssets,
-  ]
-);
 
-/// Build a macOS release application.
+  @override
-const Target macoReleaseApplication = Target(
+  Future<void> build(List<File> inputFiles, Environment environment) async {
-  name: 'release_macos_application',
+    final String basePath = artifacts.getArtifactPath(Artifact.flutterMacOSFramework);
-  buildAction: null,
+    final Directory targetDirectory = environment
-  inputs: <Source>[],
+      .projectDir
-  outputs: <Source>[],
+      .childDirectory('macos')
-  dependencies: <Target>[
+      .childDirectory('Flutter')
-    unpackMacos,
+      .childDirectory('FlutterMacOS.framework');
-    aotElfRelease,
+    if (targetDirectory.existsSync()) {
-    copyAssets,
+      targetDirectory.deleteSync(recursive: true);
-  ]
+    }
-);
+
+    final ProcessResult result = await processManager
+        .run(<String>['cp', '-R', basePath, targetDirectory.path]);
+    if (result.exitCode != 0) {
+      throw Exception(
+        'Failed to copy framework (exit ${result.exitCode}:\n'
+        '${result.stdout}\n---\n${result.stderr}',
+      );
+    }
+  }
+}

packages/flutter_tools/lib/src/build_system/targets/windows.dart

@@ -7,33 +7,21 @@ import '../../base/file_system.dart';
 import '../../globals.dart';
 import '../build_system.dart';
 
-/// Copies all of the input files to the correct copy dir.
-Future<void> copyWindowsAssets(Map<String, ChangeType> updates,
-    Environment environment) async {
-  // This path needs to match the prefix in the rule below.
-  final String basePath = artifacts.getArtifactPath(Artifact.windowsDesktopPath);
-  for (String input in updates.keys) {
-    final String outputPath = fs.path.join(
-      environment.projectDir.path,
-      'windows',
-      'flutter',
-      fs.path.relative(input, from: basePath),
-    );
-    final File destinationFile = fs.file(outputPath);
-    if (!destinationFile.parent.existsSync()) {
-      destinationFile.parent.createSync(recursive: true);
-    }
-    fs.file(input).copySync(destinationFile.path);
-  }
-}
-
 /// Copies the Windows desktop embedding files to the copy directory.
-const Target unpackWindows = Target(
+class UnpackWindows extends Target {
-  name: 'unpack_windows',
+  const UnpackWindows();
-  inputs: <Source>[
+
+  @override
+  String get name => 'unpack_windows';
+
+  @override
+  List<Source> get inputs => const <Source>[
+    Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/windows.dart'),
     Source.artifact(Artifact.windowsDesktopPath),
-  ],
+  ];
-  outputs: <Source>[
+
+  @override
+  List<Source> get outputs => const <Source>[
     Source.pattern('{PROJECT_DIR}/windows/flutter/flutter_windows.dll'),
     Source.pattern('{PROJECT_DIR}/windows/flutter/flutter_windows.dll.exp'),
     Source.pattern('{PROJECT_DIR}/windows/flutter/flutter_windows.dll.lib'),
@@ -44,7 +32,30 @@ const Target unpackWindows = Target(
     Source.pattern('{PROJECT_DIR}/windows/flutter/flutter_glfw.h'),
     Source.pattern('{PROJECT_DIR}/windows/flutter/icudtl.dat'),
     Source.pattern('{PROJECT_DIR}/windows/flutter/cpp_client_wrapper/*'),
-  ],
+  ];
-  dependencies: <Target>[],
+
-  buildAction: copyWindowsAssets,
+  @override
-);
+  List<Target> get dependencies => const <Target>[];
+
+  @override
+  Future<void> build(List<File> inputFiles, Environment environment) async {
+    // This path needs to match the prefix in the rule below.
+    final String basePath = artifacts.getArtifactPath(Artifact.windowsDesktopPath);
+    for (File input in inputFiles) {
+      if (fs.path.basename(input.path) == 'windows.dart') {
+        continue;
+      }
+      final String outputPath = fs.path.join(
+        environment.projectDir.path,
+        'windows',
+        'flutter',
+        fs.path.relative(input.path, from: basePath),
+      );
+      final File destinationFile = fs.file(outputPath);
+      if (!destinationFile.parent.existsSync()) {
+        destinationFile.parent.createSync(recursive: true);
+      }
+      fs.file(input).copySync(destinationFile.path);
+    }
+  }
+}

packages/flutter_tools/lib/src/commands/assemble.dart

@@ -4,9 +4,13 @@
 
 import '../base/common.dart';
 import '../base/context.dart';
-import '../build_info.dart';
 import '../build_system/build_system.dart';
-import '../convert.dart';
+import '../build_system/targets/assets.dart';
+import '../build_system/targets/dart.dart';
+import '../build_system/targets/ios.dart';
+import '../build_system/targets/linux.dart';
+import '../build_system/targets/macos.dart';
+import '../build_system/targets/windows.dart';
 import '../globals.dart';
 import '../project.dart';
 import '../runner/flutter_command.dart';
@@ -14,30 +18,23 @@ import '../runner/flutter_command.dart';
 /// The [BuildSystem] instance.
 BuildSystem get buildSystem => context.get<BuildSystem>();
 
+/// All currently implemented targets.
+const List<Target> _kDefaultTargets = <Target>[
+  UnpackMacOS(),
+  UnpackLinux(),
+  UnpackWindows(),
+  CopyAssets(),
+  KernelSnapshot(),
+  AotElfProfile(),
+  AotElfRelease(),
+  AotAssemblyProfile(),
+  AotAssemblyRelease(),
+];
+
 /// Assemble provides a low level API to interact with the flutter tool build
 /// system.
 class AssembleCommand extends FlutterCommand {
   AssembleCommand() {
-    addSubcommand(AssembleRun());
-    addSubcommand(AssembleDescribe());
-    addSubcommand(AssembleListInputs());
-    addSubcommand(AssembleBuildDirectory());
-  }
-  @override
-  String get description => 'Assemble and build flutter resources.';
-
-  @override
-  String get name => 'assemble';
-
-
-  @override
-  Future<FlutterCommandResult> runCommand() {
-    return null;
-  }
-}
-
-abstract class AssembleBase extends FlutterCommand {
-  AssembleBase() {
     argParser.addMultiOption(
       'define',
       abbr: 'd',
@@ -57,36 +54,19 @@ abstract class AssembleBase extends FlutterCommand {
     );
   }
 
-  /// Returns the provided target platform.
+  @override
-  ///
+  String get description => 'Assemble and build flutter resources.';
-  /// Throws a [ToolExit] if none is provided. This intentionally has no
-  /// default.
-  TargetPlatform get targetPlatform {
-    final String value = argResults['target-platform'] ?? 'darwin-x64';
-    if (value == null) {
-      throwToolExit('--target-platform is required for flutter assemble.');
-    }
-    return getTargetPlatformForName(value);
-  }
 
-  /// Returns the provided build mode.
+  @override
-  ///
+  String get name => 'assemble';
-  /// Throws a [ToolExit] if none is provided. This intentionally has no
-  /// default.
-  BuildMode get buildMode {
-    final String value = argResults['build-mode'] ?? 'debug';
-    if (value == null) {
-      throwToolExit('--build-mode is required for flutter assemble.');
-    }
-    return getBuildModeForName(value);
-  }
 
-  /// The name of the target we are describing or building.
+  /// The target we are building.
-  String get targetName {
+  Target get target {
     if (argResults.rest.isEmpty) {
       throwToolExit('missing target name for flutter assemble.');
     }
-    return argResults.rest.first;
+    final String name = argResults.rest.first;
+    return _kDefaultTargets.firstWhere((Target target) => target.name == name);
   }
 
   /// The environmental configuration for a build invocation.
@@ -115,19 +95,10 @@ abstract class AssembleBase extends FlutterCommand {
     }
     return results;
   }
-}
-
-/// Execute a build starting from a target action.
-class AssembleRun extends AssembleBase {
-  @override
-  String get description => 'Execute the stages for a specified target.';
-
-  @override
-  String get name => 'run';
 
   @override
   Future<FlutterCommandResult> runCommand() async {
-    final BuildResult result = await buildSystem.build(targetName, environment, BuildSystemConfig(
+    final BuildResult result = await buildSystem.build(target, environment, buildSystemConfig: BuildSystemConfig(
       resourcePoolSize: argResults['resource-pool-size'],
     ));
     if (!result.success) {
@@ -142,67 +113,3 @@ class AssembleRun extends AssembleBase {
     return null;
   }
 }
-
-/// Fully describe a target and its dependencies.
-class AssembleDescribe extends AssembleBase {
-  @override
-  String get description => 'List the stages for a specified target.';
-
-  @override
-  String get name => 'describe';
-
-  @override
-  Future<FlutterCommandResult> runCommand() {
-    try {
-      printStatus(
-        json.encode(buildSystem.describe(targetName, environment))
-      );
-    } on Exception catch (err, stackTrace) {
-      printTrace(stackTrace.toString());
-      throwToolExit(err.toString());
-    }
-    return null;
-  }
-}
-
-/// List input files for a target.
-class AssembleListInputs extends AssembleBase {
-  @override
-  String get description => 'List the inputs for a particular target.';
-
-  @override
-  String get name => 'inputs';
-
-  @override
-  Future<FlutterCommandResult> runCommand() {
-    try {
-      final List<Map<String, Object>> results = buildSystem.describe(targetName, environment);
-      for (Map<String, Object> result in results) {
-        if (result['name'] == targetName) {
-          final List<String> inputs = result['inputs'];
-          inputs.forEach(printStatus);
-        }
-      }
-    } on Exception catch (err, stackTrace) {
-      printTrace(stackTrace.toString());
-      throwToolExit(err.toString());
-    }
-    return null;
-  }
-}
-
-/// Return the build directory for a configuiration.
-class AssembleBuildDirectory extends AssembleBase {
-  @override
-  String get description => 'List the inputs for a particular target.';
-
-  @override
-  String get name => 'build-dir';
-
-  @override
-  Future<FlutterCommandResult> runCommand() {
-    printStatus(environment.buildDir.path);
-    return null;
-  }
-}
-

packages/flutter_tools/lib/src/context_runner.dart

@@ -69,7 +69,7 @@ Future<T> runInContext<T>(
       Artifacts: () => CachedArtifacts(),
       AssetBundleFactory: () => AssetBundleFactory.defaultInstance,
       BotDetector: () => const BotDetector(),
-      BuildSystem: () => BuildSystem(),
+      BuildSystem: () => const BuildSystem(),
       Cache: () => Cache(),
       ChromeLauncher: () => const ChromeLauncher(),
       CocoaPods: () => CocoaPods(),

packages/flutter_tools/test/general.shard/build_system/build_system_test.dart

@@ -2,14 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/platform.dart';
-import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/build_system/exceptions.dart';
-import 'package:flutter_tools/src/build_system/file_hash_store.dart';
-import 'package:flutter_tools/src/build_system/filecache.pb.dart' as pb;
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/convert.dart';
 import 'package:mockito/mockito.dart';
@@ -23,515 +19,217 @@ void main() {
     Cache.disableLocking();
   });
 
-  group(Target, () {
+  const BuildSystem buildSystem = BuildSystem();
-    Testbed testbed;
+  Testbed testbed;
-    MockPlatform mockPlatform;
+  MockPlatform mockPlatform;
-    Environment environment;
+  Environment environment;
-    Target fooTarget;
+  Target fooTarget;
-    Target barTarget;
+  Target barTarget;
-    Target fizzTarget;
+  Target fizzTarget;
-    BuildSystem buildSystem;
+  Target sharedTarget;
-    int fooInvocations;
+  int fooInvocations;
-    int barInvocations;
+  int barInvocations;
+  int shared;
 
-    setUp(() {
+  setUp(() {
-      fooInvocations = 0;
+    fooInvocations = 0;
-      barInvocations = 0;
+    barInvocations = 0;
-      mockPlatform = MockPlatform();
+    shared = 0;
-      // Keep file paths the same.
+    mockPlatform = MockPlatform();
-      when(mockPlatform.isWindows).thenReturn(false);
+    // Keep file paths the same.
-      testbed = Testbed(
+    when(mockPlatform.isWindows).thenReturn(false);
-        setup: () {
-          environment = Environment(
-            projectDir: fs.currentDirectory,
-          );
-          fs.file('foo.dart').createSync(recursive: true);
-          fs.file('pubspec.yaml').createSync();
-          fooTarget = Target(
-            name: 'foo',
-            inputs: const <Source>[
-              Source.pattern('{PROJECT_DIR}/foo.dart'),
-            ],
-            outputs: const <Source>[
-              Source.pattern('{BUILD_DIR}/out'),
-            ],
-            dependencies: <Target>[],
-            buildAction: (Map<String, ChangeType> updates, Environment environment) {
-              environment
-                .buildDir
-                .childFile('out')
-                ..createSync(recursive: true)
-                ..writeAsStringSync('hey');
-              fooInvocations++;
-            }
-          );
-          barTarget = Target(
-            name: 'bar',
-            inputs: const <Source>[
-              Source.pattern('{BUILD_DIR}/out'),
-            ],
-            outputs: const <Source>[
-              Source.pattern('{BUILD_DIR}/bar'),
-            ],
-            dependencies: <Target>[fooTarget],
-            buildAction: (Map<String, ChangeType> updates, Environment environment) {
-              environment.buildDir
-                .childFile('bar')
-                ..createSync(recursive: true)
-                ..writeAsStringSync('there');
-              barInvocations++;
-            }
-          );
-          fizzTarget = Target(
-              name: 'fizz',
-              inputs: const <Source>[
-                Source.pattern('{BUILD_DIR}/out'),
-              ],
-              outputs: const <Source>[
-                Source.pattern('{BUILD_DIR}/fizz'),
-              ],
-              dependencies: <Target>[fooTarget],
-              buildAction: (Map<String, ChangeType> updates, Environment environment) {
-                throw Exception('something bad happens');
-              }
-          );
-          buildSystem = BuildSystem(<String, Target>{
-            fooTarget.name: fooTarget,
-            barTarget.name: barTarget,
-            fizzTarget.name: fizzTarget,
-          });
-        },
-        overrides: <Type, Generator>{
-          Platform: () => mockPlatform,
-        }
-      );
-    });
 
-    test('can describe build rules', () => testbed.run(() {
+    /// Create various testing targets.
-      expect(buildSystem.describe('foo', environment), <Object>[
+    fooTarget = TestTarget((List<File> inputFiles, Environment environment) async {
-        <String, Object>{
+      environment
-          'name': 'foo',
+        .buildDir
-          'dependencies': <String>[],
+        .childFile('out')
-          'inputs': <String>['/foo.dart'],
+        ..createSync(recursive: true)
-          'outputs': <String>[fs.path.join(environment.buildDir.path, 'out')],
+        ..writeAsStringSync('hey');
-          'stamp': fs.path.join(environment.buildDir.path, 'foo.stamp'),
+      fooInvocations++;
-        }
+    })
-      ]);
+      ..name = 'foo'
-    }));
+      ..inputs = const <Source>[
-
+        Source.pattern('{PROJECT_DIR}/foo.dart'),
-    test('Throws exception if asked to build non-existent target', () => testbed.run(() {
+      ]
-      expect(buildSystem.build('not_real', environment, const BuildSystemConfig()), throwsA(isInstanceOf<Exception>()));
+      ..outputs = const <Source>[
-    }));
+        Source.pattern('{BUILD_DIR}/out'),
-
+      ]
-    test('Throws exception if asked to build with missing inputs', () => testbed.run(() async {
+      ..dependencies = <Target>[];
-      // Delete required input file.
+    barTarget = TestTarget((List<File> inputFiles, Environment environment) async {
-      fs.file('foo.dart').deleteSync();
+      environment.buildDir
-      final BuildResult buildResult = await buildSystem.build('foo', environment, const BuildSystemConfig());
+        .childFile('bar')
-
+        ..createSync(recursive: true)
-      expect(buildResult.hasException, true);
+        ..writeAsStringSync('there');
-      expect(buildResult.exceptions.values.single.exception, isInstanceOf<MissingInputException>());
+      barInvocations++;
-    }));
+    })
-
+      ..name = 'bar'
-    test('Throws exception if it does not produce a specified output', () => testbed.run(() async {
+      ..inputs = const <Source>[
-      final Target badTarget = Target
+        Source.pattern('{BUILD_DIR}/out'),
-        (buildAction: (Map<String, ChangeType> inputs, Environment environment) {},
+      ]
-        inputs: const <Source>[
+      ..outputs = const <Source>[
-          Source.pattern('{PROJECT_DIR}/foo.dart'),
+        Source.pattern('{BUILD_DIR}/bar'),
-        ],
+      ]
-        outputs: const <Source>[
+      ..dependencies = <Target>[];
-          Source.pattern('{BUILD_DIR}/out')
+    fizzTarget = TestTarget((List<File> inputFiles, Environment environment) async {
-        ],
+      throw Exception('something bad happens');
-        name: 'bad'
+    })
-      );
+      ..name = 'fizz'
-      buildSystem = BuildSystem(<String, Target>{
+      ..inputs = const <Source>[
-        badTarget.name: badTarget,
+        Source.pattern('{BUILD_DIR}/out'),
-      });
+      ]
-      final BuildResult result = await buildSystem.build('bad', environment, const BuildSystemConfig());
+      ..outputs = const <Source>[
-
+        Source.pattern('{BUILD_DIR}/fizz'),
-      expect(result.hasException, true);
+      ]
-      expect(result.exceptions.values.single.exception, isInstanceOf<MissingOutputException>());
+      ..dependencies = <Target>[fooTarget];
-    }));
+    sharedTarget = TestTarget((List<File> inputFiles, Environment environment) async {
-
+      shared += 1;
-    test('Saves a stamp file with inputs and outputs', () => testbed.run(() async {
+    })
-      await buildSystem.build('foo', environment, const BuildSystemConfig());
+      ..name = 'shared'
-
+      ..inputs = const <Source>[
-      final File stampFile = fs.file(fs.path.join(environment.buildDir.path, 'foo.stamp'));
+        Source.pattern('{PROJECT_DIR}/foo.dart'),
-      expect(stampFile.existsSync(), true);
+      ];
-
+    testbed = Testbed(
-      final Map<String, Object> stampContents = json.decode(stampFile.readAsStringSync());
+      setup: () {
-      expect(stampContents['inputs'], <Object>['/foo.dart']);
-    }));
-
-    test('Does not re-invoke build if stamp is valid', () => testbed.run(() async {
-      await buildSystem.build('foo', environment, const BuildSystemConfig());
-      await buildSystem.build('foo', environment, const BuildSystemConfig());
-
-      expect(fooInvocations, 1);
-    }));
-
-    test('Re-invoke build if input is modified', () => testbed.run(() async {
-      await buildSystem.build('foo', environment, const BuildSystemConfig());
-
-      fs.file('foo.dart').writeAsStringSync('new contents');
-
-      await buildSystem.build('foo', environment, const BuildSystemConfig());
-      expect(fooInvocations, 2);
-    }));
-
-    test('does not re-invoke build if input timestamp changes', () => testbed.run(() async {
-      await buildSystem.build('foo', environment, const BuildSystemConfig());
-
-      fs.file('foo.dart').writeAsStringSync('');
-
-      await buildSystem.build('foo', environment, const BuildSystemConfig());
-      expect(fooInvocations, 1);
-    }));
-
-    test('does not re-invoke build if output timestamp changes', () => testbed.run(() async {
-      await buildSystem.build('foo', environment, const BuildSystemConfig());
-
-      environment.buildDir.childFile('out').writeAsStringSync('hey');
-
-      await buildSystem.build('foo', environment, const BuildSystemConfig());
-      expect(fooInvocations, 1);
-    }));
-
-
-    test('Re-invoke build if output is modified', () => testbed.run(() async {
-      await buildSystem.build('foo', environment, const BuildSystemConfig());
-
-      environment.buildDir.childFile('out').writeAsStringSync('Something different');
-
-      await buildSystem.build('foo', environment, const BuildSystemConfig());
-      expect(fooInvocations, 2);
-    }));
-
-    test('Runs dependencies of targets', () => testbed.run(() async {
-      await buildSystem.build('bar', environment, const BuildSystemConfig());
-
-      expect(fs.file(fs.path.join(environment.buildDir.path, 'bar')).existsSync(), true);
-      expect(fooInvocations, 1);
-      expect(barInvocations, 1);
-    }));
-
-    test('handles a throwing build action', () => testbed.run(() async {
-      final BuildResult result = await buildSystem.build('fizz', environment, const BuildSystemConfig());
-
-      expect(result.hasException, true);
-    }));
-
-    test('Can describe itself with JSON output', () => testbed.run(() {
-      environment.buildDir.createSync(recursive: true);
-      expect(fooTarget.toJson(environment), <String, dynamic>{
-        'inputs':  <Object>[
-          '/foo.dart'
-        ],
-        'outputs': <Object>[
-          fs.path.join(environment.buildDir.path, 'out'),
-        ],
-        'dependencies': <Object>[],
-        'name':  'foo',
-        'stamp': fs.path.join(environment.buildDir.path, 'foo.stamp'),
-      });
-    }));
-
-    test('Compute update recognizes added files', () => testbed.run(() async {
-      fs.directory('build').createSync();
-      final FileHashStore fileCache = FileHashStore(environment);
-      fileCache.initialize();
-      final List<File> inputs = fooTarget.resolveInputs(environment);
-      final Map<String, ChangeType> changes = await fooTarget.computeChanges(inputs, environment, fileCache);
-      fileCache.persist();
-
-      expect(changes, <String, ChangeType>{
-        '/foo.dart': ChangeType.Added
-      });
-
-      await buildSystem.build('foo', environment, const BuildSystemConfig());
-      final Map<String, ChangeType> secondChanges = await fooTarget.computeChanges(inputs, environment, fileCache);
-
-      expect(secondChanges, <String, ChangeType>{});
-    }));
-  });
-
-  group('FileCache', () {
-    Testbed testbed;
-    Environment environment;
-
-    setUp(() {
-      testbed = Testbed(setup: () {
-        fs.directory('build').createSync();
         environment = Environment(
           projectDir: fs.currentDirectory,
         );
-      });
+        fs.file('foo.dart')
-    });
+          ..createSync(recursive: true)
-
+          ..writeAsStringSync('');
-    test('Initializes file cache', () => testbed.run(() {
+        fs.file('pubspec.yaml').createSync();
-      final FileHashStore fileCache = FileHashStore(environment);
+      },
-      fileCache.initialize();
+      overrides: <Type, Generator>{
-      fileCache.persist();
+        Platform: () => mockPlatform,
-
+      }
-      expect(fs.file(fs.path.join('build', '.filecache')).existsSync(), true);
+    );
-
-      final List<int> buffer = fs.file(fs.path.join('build', '.filecache')).readAsBytesSync();
-      final pb.FileStorage fileStorage = pb.FileStorage.fromBuffer(buffer);
-
-      expect(fileStorage.files, isEmpty);
-      expect(fileStorage.version, 1);
-    }));
-
-    test('saves and restores to file cache', () => testbed.run(() {
-      final File file = fs.file('foo.dart')
-        ..createSync()
-        ..writeAsStringSync('hello');
-      final FileHashStore fileCache = FileHashStore(environment);
-      fileCache.initialize();
-      fileCache.hashFiles(<File>[file]);
-      fileCache.persist();
-      final String currentHash =  fileCache.currentHashes[file.resolveSymbolicLinksSync()];
-      final List<int> buffer = fs.file(fs.path.join('build', '.filecache')).readAsBytesSync();
-      pb.FileStorage fileStorage = pb.FileStorage.fromBuffer(buffer);
-
-      expect(fileStorage.files.single.hash, currentHash);
-      expect(fileStorage.files.single.path, file.resolveSymbolicLinksSync());
-
-
-      final FileHashStore newFileCache = FileHashStore(environment);
-      newFileCache.initialize();
-      expect(newFileCache.currentHashes, isEmpty);
-      expect(newFileCache.previousHashes[fs.path.absolute('foo.dart')],  currentHash);
-      newFileCache.persist();
-
-      // Still persisted correctly.
-      fileStorage = pb.FileStorage.fromBuffer(buffer);
-
-      expect(fileStorage.files.single.hash, currentHash);
-      expect(fileStorage.files.single.path, file.resolveSymbolicLinksSync());
-    }));
   });
 
-  group('Target', () {
+  test('Throws exception if asked to build with missing inputs', () => testbed.run(() async {
-    Testbed testbed;
+    // Delete required input file.
-    MockPlatform mockPlatform;
+    fs.file('foo.dart').deleteSync();
-    Environment environment;
+    final BuildResult buildResult = await buildSystem.build(fooTarget, environment);
-    Target sharedTarget;
-    BuildSystem buildSystem;
-    int shared;
 
-    setUp(() {
+    expect(buildResult.hasException, true);
-      shared = 0;
+    expect(buildResult.exceptions.values.single.exception, isInstanceOf<MissingInputException>());
-      Cache.flutterRoot = '';
+  }));
-      mockPlatform = MockPlatform();
+
-      // Keep file paths the same.
+  test('Throws exception if it does not produce a specified output', () => testbed.run(() async {
-      when(mockPlatform.isWindows).thenReturn(false);
+    final Target badTarget = TestTarget((List<File> inputFiles, Environment environment) async {})
-      when(mockPlatform.isLinux).thenReturn(true);
+      ..inputs = const <Source>[
-      when(mockPlatform.isMacOS).thenReturn(false);
+        Source.pattern('{PROJECT_DIR}/foo.dart'),
-      testbed = Testbed(
+      ]
-          setup: () {
+      ..outputs = const <Source>[
-            environment = Environment(
+        Source.pattern('{BUILD_DIR}/out')
-              projectDir: fs.currentDirectory,
+      ];
-            );
+    final BuildResult result = await buildSystem.build(badTarget, environment);
-            fs.file('foo.dart').createSync(recursive: true);
+
-            fs.file('pubspec.yaml').createSync();
+    expect(result.hasException, true);
-            sharedTarget = Target(
+    expect(result.exceptions.values.single.exception, isInstanceOf<MissingOutputException>());
-              name: 'shared',
+  }));
-              inputs: const <Source>[
+
-                Source.pattern('{PROJECT_DIR}/foo.dart'),
+  test('Saves a stamp file with inputs and outputs', () => testbed.run(() async {
-              ],
+    await buildSystem.build(fooTarget, environment);
-              outputs: const <Source>[],
+
-              dependencies: <Target>[],
+    final File stampFile = fs.file(fs.path.join(environment.buildDir.path, 'foo.stamp'));
-              buildAction: (Map<String, ChangeType> updates, Environment environment) {
+    expect(stampFile.existsSync(), true);
-                shared += 1;
+
-              }
+    final Map<String, Object> stampContents = json.decode(stampFile.readAsStringSync());
-            );
+    expect(stampContents['inputs'], <Object>['/foo.dart']);
-            final Target fooTarget = Target(
+  }));
-                name: 'foo',
+
-                inputs: const <Source>[
+  test('Does not re-invoke build if stamp is valid', () => testbed.run(() async {
-                  Source.pattern('{PROJECT_DIR}/foo.dart'),
+    await buildSystem.build(fooTarget, environment);
-                ],
+    await buildSystem.build(fooTarget, environment);
-                outputs: const <Source>[
+
-                  Source.pattern('{BUILD_DIR}/out'),
+    expect(fooInvocations, 1);
-                ],
+  }));
-                dependencies: <Target>[sharedTarget],
+
-                buildAction: (Map<String, ChangeType> updates, Environment environment) {
+  test('Re-invoke build if input is modified', () => testbed.run(() async {
-                  environment
+    await buildSystem.build(fooTarget, environment);
-                    .buildDir
+
-                    .childFile('out')
+    fs.file('foo.dart').writeAsStringSync('new contents');
-                    ..createSync(recursive: true)
+
-                    ..writeAsStringSync('hey');
+    await buildSystem.build(fooTarget, environment);
-                }
+    expect(fooInvocations, 2);
-            );
+  }));
-            final Target barTarget = Target(
+
-                name: 'bar',
+  test('does not re-invoke build if input timestamp changes', () => testbed.run(() async {
-                inputs: const <Source>[
+    await buildSystem.build(fooTarget, environment);
-                  Source.pattern('{BUILD_DIR}/out'),
+
-                ],
+    fs.file('foo.dart').writeAsStringSync('');
-                outputs: const <Source>[
+
-                  Source.pattern('{BUILD_DIR}/bar'),
+    await buildSystem.build(fooTarget, environment);
-                ],
+    expect(fooInvocations, 1);
-                dependencies: <Target>[fooTarget, sharedTarget],
+  }));
-                buildAction: (Map<String, ChangeType> updates, Environment environment) {
+
-                  environment
+  test('does not re-invoke build if output timestamp changes', () => testbed.run(() async {
-                    .buildDir
+    await buildSystem.build(fooTarget, environment);
-                    .childFile('bar')
+
-                    ..createSync(recursive: true)
+    environment.buildDir.childFile('out').writeAsStringSync('hey');
-                    ..writeAsStringSync('there');
+
-                }
+    await buildSystem.build(fooTarget, environment);
-            );
+    expect(fooInvocations, 1);
-            buildSystem = BuildSystem(<String, Target>{
+  }));
-              fooTarget.name: fooTarget,
+
-              barTarget.name: barTarget,
+
-              sharedTarget.name: sharedTarget,
+  test('Re-invoke build if output is modified', () => testbed.run(() async {
-            });
+    await buildSystem.build(fooTarget, environment);
-          },
+
-          overrides: <Type, Generator>{
+    environment.buildDir.childFile('out').writeAsStringSync('Something different');
-            Platform: () => mockPlatform,
+
-          }
+    await buildSystem.build(fooTarget, environment);
-      );
+    expect(fooInvocations, 2);
+  }));
+
+  test('Runs dependencies of targets', () => testbed.run(() async {
+    barTarget.dependencies.add(fooTarget);
+
+    await buildSystem.build(barTarget, environment);
+
+    expect(fs.file(fs.path.join(environment.buildDir.path, 'bar')).existsSync(), true);
+    expect(fooInvocations, 1);
+    expect(barInvocations, 1);
+  }));
+
+  test('Only invokes shared dependencies once', () => testbed.run(() async {
+    fooTarget.dependencies.add(sharedTarget);
+    barTarget.dependencies.add(sharedTarget);
+    barTarget.dependencies.add(fooTarget);
+
+    await buildSystem.build(barTarget, environment);
+
+    expect(shared, 1);
+  }));
+
+
+  test('handles a throwing build action', () => testbed.run(() async {
+    final BuildResult result = await buildSystem.build(fizzTarget, environment);
+
+    expect(result.hasException, true);
+  }));
+
+  test('Can describe itself with JSON output', () => testbed.run(() {
+    environment.buildDir.createSync(recursive: true);
+    expect(fooTarget.toJson(environment), <String, dynamic>{
+      'inputs':  <Object>[
+        '/foo.dart'
+      ],
+      'outputs': <Object>[
+        fs.path.join(environment.buildDir.path, 'out'),
+      ],
+      'dependencies': <Object>[],
+      'name':  'foo',
+      'stamp': fs.path.join(environment.buildDir.path, 'foo.stamp'),
     });
-
+  }));
-    test('Only invokes shared target once', () => testbed.run(() async {
-      await buildSystem.build('bar', environment, const BuildSystemConfig());
-
-      expect(shared, 1);
-    }));
-  });
-
-  group('Source', () {
-    Testbed testbed;
-    SourceVisitor visitor;
-    Environment environment;
-
-    setUp(() {
-      testbed = Testbed(setup: () {
-        fs.directory('cache').createSync();
-        environment = Environment(
-          projectDir: fs.currentDirectory,
-          buildDir: fs.directory('build'),
-        );
-        visitor = SourceVisitor(environment);
-        environment.buildDir.createSync(recursive: true);
-      });
-    });
-
-    test('configures implicit vs explict correctly', () => testbed.run(() {
-      expect(const Source.pattern('{PROJECT_DIR}/foo').implicit, false);
-      expect(const Source.pattern('{PROJECT_DIR}/*foo').implicit, true);
-      expect(Source.function((Environment environment) => <File>[]).implicit, true);
-      expect(Source.behavior(TestBehavior()).implicit, true);
-    }));
-
-    test('can substitute {PROJECT_DIR}/foo', () => testbed.run(() {
-      fs.file('foo').createSync();
-      const Source fooSource = Source.pattern('{PROJECT_DIR}/foo');
-      fooSource.accept(visitor);
-
-      expect(visitor.sources.single.path, fs.path.absolute('foo'));
-    }));
-
-    test('can substitute {BUILD_DIR}/bar', () => testbed.run(() {
-      final String path = fs.path.join(environment.buildDir.path, 'bar');
-      fs.file(path).createSync();
-      const Source barSource = Source.pattern('{BUILD_DIR}/bar');
-      barSource.accept(visitor);
-
-      expect(visitor.sources.single.path, fs.path.absolute(path));
-    }));
-
-    test('can substitute Artifact', () => testbed.run(() {
-      final String path = fs.path.join(
-        Cache.instance.getArtifactDirectory('engine').path,
-        'windows-x64',
-        'foo',
-      );
-      fs.file(path).createSync(recursive: true);
-      const Source fizzSource = Source.artifact(Artifact.windowsDesktopPath, platform: TargetPlatform.windows_x64);
-      fizzSource.accept(visitor);
-
-      expect(visitor.sources.single.resolveSymbolicLinksSync(), fs.path.absolute(path));
-    }));
-
-    test('can substitute {PROJECT_DIR}/*.fizz', () => testbed.run(() {
-      const Source fizzSource = Source.pattern('{PROJECT_DIR}/*.fizz');
-      fizzSource.accept(visitor);
-
-      expect(visitor.sources, isEmpty);
-
-      fs.file('foo.fizz').createSync();
-      fs.file('foofizz').createSync();
-
-
-      fizzSource.accept(visitor);
-
-      expect(visitor.sources.single.path, fs.path.absolute('foo.fizz'));
-    }));
-
-    test('can substitute {PROJECT_DIR}/fizz.*', () => testbed.run(() {
-      const Source fizzSource = Source.pattern('{PROJECT_DIR}/fizz.*');
-      fizzSource.accept(visitor);
-
-      expect(visitor.sources, isEmpty);
-
-      fs.file('fizz.foo').createSync();
-      fs.file('fizz').createSync();
-
-      fizzSource.accept(visitor);
-
-      expect(visitor.sources.single.path, fs.path.absolute('fizz.foo'));
-    }));
-
-
-    test('can substitute {PROJECT_DIR}/a*bc', () => testbed.run(() {
-      const Source fizzSource = Source.pattern('{PROJECT_DIR}/bc*bc');
-      fizzSource.accept(visitor);
-
-      expect(visitor.sources, isEmpty);
-
-      fs.file('bcbc').createSync();
-      fs.file('bc').createSync();
-
-      fizzSource.accept(visitor);
-
-      expect(visitor.sources.single.path, fs.path.absolute('bcbc'));
-    }));
-
-
-    test('crashes on bad substitute of two **', () => testbed.run(() {
-      const Source fizzSource = Source.pattern('{PROJECT_DIR}/*.*bar');
-
-      fs.file('abcd.bar').createSync();
-
-      expect(() => fizzSource.accept(visitor), throwsA(isInstanceOf<InvalidPatternException>()));
-    }));
-
-
-    test('can\'t substitute foo', () => testbed.run(() {
-      const Source invalidBase = Source.pattern('foo');
-
-      expect(() => invalidBase.accept(visitor), throwsA(isInstanceOf<InvalidPatternException>()));
-    }));
-  });
-
-
 
   test('Can find dependency cycles', () {
-    final Target barTarget = Target(
+    final Target barTarget = TestTarget()..name = 'bar';
-      name: 'bar',
+    final Target fooTarget = TestTarget()..name = 'foo';
-      inputs: <Source>[],
-      outputs: <Source>[],
-      buildAction: null,
-      dependencies: nonconst(<Target>[])
-    );
-    final Target fooTarget = Target(
-      name: 'foo',
-      inputs: <Source>[],
-      outputs: <Source>[],
-      buildAction: null,
-      dependencies: nonconst(<Target>[])
-    );
     barTarget.dependencies.add(fooTarget);
     fooTarget.dependencies.add(barTarget);
+
     expect(() => checkCycles(barTarget), throwsA(isInstanceOf<CycleException>()));
   });
 }
@@ -541,14 +239,23 @@ class MockPlatform extends Mock implements Platform {}
 // Work-around for silly lint check.
 T nonconst<T>(T input) => input;
 
-class TestBehavior extends SourceBehavior {
+class TestTarget extends Target {
-  @override
+  TestTarget([this._build]);
-  List<File> inputs(Environment environment) {
+
-    return null;
+  final Future<void> Function(List<File> inputFiles, Environment environment) _build;
-  }
 
   @override
-  List<File> outputs(Environment environment) {
+  Future<void> build(List<File> inputFiles, Environment environment) => _build(inputFiles, environment);
-    return null;
+
-  }
+  @override
+  List<Target> dependencies = <Target>[];
+
+  @override
+  List<Source> inputs = <Source>[];
+
+  @override
+  String name = 'test';
+
+  @override
+  List<Source> outputs = <Source>[];
 }

packages/flutter_tools/test/general.shard/build_system/exceptions_test.dart

@@ -12,19 +12,9 @@ void main() {
   test('Exceptions', () {
     final MissingInputException missingInputException = MissingInputException(
         <File>[fs.file('foo'), fs.file('bar')], 'example');
-    final CycleException cycleException = CycleException(const <Target>{
+    final CycleException cycleException = CycleException(<Target>{
-      Target(
+      TestTarget()..name = 'foo',
-        name: 'foo',
+      TestTarget()..name = 'bar',
-        buildAction: null,
-        inputs: <Source>[],
-        outputs: <Source>[],
-      ),
-      Target(
-        name: 'bar',
-        buildAction: null,
-        inputs: <Source>[],
-        outputs: <Source>[],
-      )
     });
     final InvalidPatternException invalidPatternException = InvalidPatternException(
       'ABC'
@@ -70,3 +60,24 @@ void main() {
     );
   });
 }
+
+class TestTarget extends Target {
+  TestTarget([this._build]);
+
+  final Future<void> Function(List<File> inputFiles, Environment environment) _build;
+
+  @override
+  Future<void> build(List<File> inputFiles, Environment environment) => _build(inputFiles, environment);
+
+  @override
+  List<Target> dependencies = <Target>[];
+
+  @override
+  List<Source> inputs = <Source>[];
+
+  @override
+  String name = 'test';
+
+  @override
+  List<Source> outputs = <Source>[];
+}

packages/flutter_tools/test/general.shard/build_system/filecache_test.dart

@@ -0,0 +1,68 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/build_system/build_system.dart';
+import 'package:flutter_tools/src/build_system/file_hash_store.dart';
+import 'package:flutter_tools/src/build_system/filecache.pb.dart' as pb;
+
+import '../../src/common.dart';
+import '../../src/testbed.dart';
+
+void main() {
+  Testbed testbed;
+  Environment environment;
+
+  setUp(() {
+    testbed = Testbed(setup: () {
+      fs.directory('build').createSync();
+      environment = Environment(
+        projectDir: fs.currentDirectory,
+      );
+    });
+  });
+
+  test('Initializes file cache', () => testbed.run(() {
+    final FileHashStore fileCache = FileHashStore(environment);
+    fileCache.initialize();
+    fileCache.persist();
+
+    expect(fs.file(fs.path.join('build', '.filecache')).existsSync(), true);
+
+    final List<int> buffer = fs.file(fs.path.join('build', '.filecache')).readAsBytesSync();
+    final pb.FileStorage fileStorage = pb.FileStorage.fromBuffer(buffer);
+
+    expect(fileStorage.files, isEmpty);
+    expect(fileStorage.version, 1);
+  }));
+
+  test('saves and restores to file cache', () => testbed.run(() {
+    final File file = fs.file('foo.dart')
+      ..createSync()
+      ..writeAsStringSync('hello');
+    final FileHashStore fileCache = FileHashStore(environment);
+    fileCache.initialize();
+    fileCache.hashFiles(<File>[file]);
+    fileCache.persist();
+    final String currentHash =  fileCache.currentHashes[file.resolveSymbolicLinksSync()];
+    final List<int> buffer = fs.file(fs.path.join('build', '.filecache')).readAsBytesSync();
+    pb.FileStorage fileStorage = pb.FileStorage.fromBuffer(buffer);
+
+    expect(fileStorage.files.single.hash, currentHash);
+    expect(fileStorage.files.single.path, file.resolveSymbolicLinksSync());
+
+
+    final FileHashStore newFileCache = FileHashStore(environment);
+    newFileCache.initialize();
+    expect(newFileCache.currentHashes, isEmpty);
+    expect(newFileCache.previousHashes[fs.path.absolute('foo.dart')],  currentHash);
+    newFileCache.persist();
+
+    // Still persisted correctly.
+    fileStorage = pb.FileStorage.fromBuffer(buffer);
+
+    expect(fileStorage.files.single.hash, currentHash);
+    expect(fileStorage.files.single.path, file.resolveSymbolicLinksSync());
+  }));
+}

packages/flutter_tools/test/general.shard/build_system/source_test.dart

@@ -0,0 +1,150 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter_tools/src/artifacts.dart';
+import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/build_info.dart';
+import 'package:flutter_tools/src/build_system/build_system.dart';
+import 'package:flutter_tools/src/build_system/exceptions.dart';
+import 'package:flutter_tools/src/build_system/source.dart';
+import 'package:flutter_tools/src/cache.dart';
+
+import '../../src/common.dart';
+import '../../src/testbed.dart';
+
+void main() {
+  Testbed testbed;
+  SourceVisitor visitor;
+  Environment environment;
+
+  setUp(() {
+    testbed = Testbed(setup: () {
+      fs.directory('cache').createSync();
+      environment = Environment(
+        projectDir: fs.currentDirectory,
+        buildDir: fs.directory('build'),
+      );
+      visitor = SourceVisitor(environment);
+      environment.buildDir.createSync(recursive: true);
+    });
+  });
+
+  test('configures implicit vs explict correctly', () => testbed.run(() {
+    expect(const Source.pattern('{PROJECT_DIR}/foo').implicit, false);
+    expect(const Source.pattern('{PROJECT_DIR}/*foo').implicit, true);
+    expect(Source.function((Environment environment) => <File>[]).implicit, true);
+    expect(Source.behavior(TestBehavior()).implicit, true);
+  }));
+
+  test('can substitute {PROJECT_DIR}/foo', () => testbed.run(() {
+    fs.file('foo').createSync();
+    const Source fooSource = Source.pattern('{PROJECT_DIR}/foo');
+    fooSource.accept(visitor);
+
+    expect(visitor.sources.single.path, fs.path.absolute('foo'));
+  }));
+
+  test('can substitute {BUILD_DIR}/bar', () => testbed.run(() {
+    final String path = fs.path.join(environment.buildDir.path, 'bar');
+    fs.file(path).createSync();
+    const Source barSource = Source.pattern('{BUILD_DIR}/bar');
+    barSource.accept(visitor);
+
+    expect(visitor.sources.single.path, fs.path.absolute(path));
+  }));
+
+  test('can substitute {FLUTTER_ROOT}/foo', () => testbed.run(() {
+    final String path = fs.path.join(environment.flutterRootDir.path, 'foo');
+    fs.file(path).createSync();
+    const Source barSource = Source.pattern('{FLUTTER_ROOT}/foo');
+    barSource.accept(visitor);
+
+    expect(visitor.sources.single.path, fs.path.absolute(path));
+  }));
+
+  test('can substitute Artifact', () => testbed.run(() {
+    final String path = fs.path.join(
+      Cache.instance.getArtifactDirectory('engine').path,
+      'windows-x64',
+      'foo',
+    );
+    fs.file(path).createSync(recursive: true);
+    const Source fizzSource = Source.artifact(Artifact.windowsDesktopPath, platform: TargetPlatform.windows_x64);
+    fizzSource.accept(visitor);
+
+    expect(visitor.sources.single.resolveSymbolicLinksSync(), fs.path.absolute(path));
+  }));
+
+  test('can substitute {PROJECT_DIR}/*.fizz', () => testbed.run(() {
+    const Source fizzSource = Source.pattern('{PROJECT_DIR}/*.fizz');
+    fizzSource.accept(visitor);
+
+    expect(visitor.sources, isEmpty);
+
+    fs.file('foo.fizz').createSync();
+    fs.file('foofizz').createSync();
+
+
+    fizzSource.accept(visitor);
+
+    expect(visitor.sources.single.path, fs.path.absolute('foo.fizz'));
+  }));
+
+  test('can substitute {PROJECT_DIR}/fizz.*', () => testbed.run(() {
+    const Source fizzSource = Source.pattern('{PROJECT_DIR}/fizz.*');
+    fizzSource.accept(visitor);
+
+    expect(visitor.sources, isEmpty);
+
+    fs.file('fizz.foo').createSync();
+    fs.file('fizz').createSync();
+
+    fizzSource.accept(visitor);
+
+    expect(visitor.sources.single.path, fs.path.absolute('fizz.foo'));
+  }));
+
+
+  test('can substitute {PROJECT_DIR}/a*bc', () => testbed.run(() {
+    const Source fizzSource = Source.pattern('{PROJECT_DIR}/bc*bc');
+    fizzSource.accept(visitor);
+
+    expect(visitor.sources, isEmpty);
+
+    fs.file('bcbc').createSync();
+    fs.file('bc').createSync();
+
+    fizzSource.accept(visitor);
+
+    expect(visitor.sources.single.path, fs.path.absolute('bcbc'));
+  }));
+
+
+  test('crashes on bad substitute of two **', () => testbed.run(() {
+    const Source fizzSource = Source.pattern('{PROJECT_DIR}/*.*bar');
+
+    fs.file('abcd.bar').createSync();
+
+    expect(() => fizzSource.accept(visitor), throwsA(isInstanceOf<InvalidPatternException>()));
+  }));
+
+
+  test('can\'t substitute foo', () => testbed.run(() {
+    const Source invalidBase = Source.pattern('foo');
+
+    expect(() => invalidBase.accept(visitor), throwsA(isInstanceOf<InvalidPatternException>()));
+  }));
+}
+
+class TestBehavior extends SourceBehavior {
+  @override
+  List<File> inputs(Environment environment) {
+    return null;
+  }
+
+  @override
+  List<File> outputs(Environment environment) {
+    return null;
+  }
+}

packages/flutter_tools/test/general.shard/build_system/targets/assets_test.dart

@@ -10,61 +10,59 @@ import '../../../src/common.dart';
 import '../../../src/testbed.dart';
 
 void main() {
-  group('copy_assets', () {
+  const BuildSystem buildSystem = BuildSystem();
-    Testbed testbed;
+  Environment environment;
-    BuildSystem buildSystem;
+  Testbed testbed;
-    Environment environment;
 
-    setUp(() {
+  setUp(() {
-      testbed = Testbed(setup: () {
+    testbed = Testbed(setup: () {
-        environment = Environment(
+      environment = Environment(
-          projectDir: fs.currentDirectory,
+        projectDir: fs.currentDirectory,
-        );
+      );
-        buildSystem = BuildSystem(<String, Target>{
+      fs.file(fs.path.join('packages', 'flutter_tools', 'lib', 'src',
-          copyAssets.name: copyAssets,
+          'build_system', 'targets', 'assets.dart'))
-        });
+        ..createSync(recursive: true);
-        fs.file(fs.path.join('assets', 'foo', 'bar.png'))
+      fs.file(fs.path.join('assets', 'foo', 'bar.png'))
-          ..createSync(recursive: true);
+        ..createSync(recursive: true);
-        fs.file('.packages')
+      fs.file('.packages')
-          ..createSync();
+        ..createSync();
-        fs.file('pubspec.yaml')
-          ..createSync()
-          ..writeAsStringSync('''
-name: example
-
-flutter:
-  assets:
-    - assets/foo/bar.png
-''');
-      });
-    });
-
-    test('Copies files to correct asset directory', () => testbed.run(() async {
-      await buildSystem.build('copy_assets', environment, const BuildSystemConfig());
-
-      expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'AssetManifest.json')).existsSync(), true);
-      expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'FontManifest.json')).existsSync(), true);
-      expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'LICENSE')).existsSync(), true);
-      // See https://github.com/flutter/flutter/issues/35293
-      expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets/foo/bar.png')).existsSync(), true);
-    }));
-
-    test('Does not leave stale files in build directory', () => testbed.run(() async {
-      await buildSystem.build('copy_assets', environment, const BuildSystemConfig());
-
-      expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets/foo/bar.png')).existsSync(), true);
-      // Modify manifest to remove asset.
       fs.file('pubspec.yaml')
         ..createSync()
         ..writeAsStringSync('''
 name: example
 
 flutter:
+  assets:
+    - assets/foo/bar.png
 ''');
-      await buildSystem.build('copy_assets', environment, const BuildSystemConfig());
+    });
-
-      // See https://github.com/flutter/flutter/issues/35293
-      expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets/foo/bar.png')).existsSync(), false);
-    }));
   });
+
+  test('Copies files to correct asset directory', () => testbed.run(() async {
+    await buildSystem.build(const CopyAssets(), environment);
+
+    expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'AssetManifest.json')).existsSync(), true);
+    expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'FontManifest.json')).existsSync(), true);
+    expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'LICENSE')).existsSync(), true);
+    // See https://github.com/flutter/flutter/issues/35293
+    expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets/foo/bar.png')).existsSync(), true);
+  }));
+
+  test('Does not leave stale files in build directory', () => testbed.run(() async {
+    await buildSystem.build(const CopyAssets(), environment);
+
+    expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets/foo/bar.png')).existsSync(), true);
+    // Modify manifest to remove asset.
+    fs.file('pubspec.yaml')
+      ..createSync()
+      ..writeAsStringSync('''
+name: example
+
+flutter:
+''');
+    await buildSystem.build(const CopyAssets(), environment);
+
+    // See https://github.com/flutter/flutter/issues/35293
+    expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets/foo/bar.png')).existsSync(), false);
+  }));
 }

packages/flutter_tools/test/general.shard/build_system/targets/dart_test.dart

@@ -10,6 +10,7 @@ import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/build_system/exceptions.dart';
 import 'package:flutter_tools/src/build_system/targets/dart.dart';
+import 'package:flutter_tools/src/build_system/targets/ios.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/compile.dart';
 import 'package:flutter_tools/src/macos/xcode.dart';
@@ -22,221 +23,234 @@ import '../../../src/mocks.dart';
 import '../../../src/testbed.dart';
 
 void main() {
-  group('dart rules', () {
+  const BuildSystem buildSystem = BuildSystem();
-    Testbed testbed;
+  Testbed testbed;
-    BuildSystem buildSystem;
+  Environment androidEnvironment;
-    Environment androidEnvironment;
+  Environment iosEnvironment;
-    Environment iosEnvironment;
+  MockProcessManager mockProcessManager;
-    MockProcessManager mockProcessManager;
+  MockXcode mockXcode;
-    MockXcode mockXcode;
 
-    setUpAll(() {
+  setUpAll(() {
-      Cache.disableLocking();
+    Cache.disableLocking();
-    });
+  });
 
-    setUp(() {
+  setUp(() {
-      mockProcessManager = MockProcessManager();
+    mockXcode = MockXcode();
-      mockXcode = MockXcode();
+    mockProcessManager = MockProcessManager();
-      testbed = Testbed(setup: () {
+    testbed = Testbed(setup: () {
-        androidEnvironment = Environment(
+      androidEnvironment = Environment(
-          projectDir: fs.currentDirectory,
+        projectDir: fs.currentDirectory,
-          defines: <String, String>{
+        defines: <String, String>{
-            kBuildMode: getNameForBuildMode(BuildMode.profile),
+          kBuildMode: getNameForBuildMode(BuildMode.profile),
-            kTargetPlatform: getNameForTargetPlatform(TargetPlatform.android_arm),
+          kTargetPlatform: getNameForTargetPlatform(TargetPlatform.android_arm),
-          }
-        );
-        iosEnvironment = Environment(
-          projectDir: fs.currentDirectory,
-          defines: <String, String>{
-            kBuildMode: getNameForBuildMode(BuildMode.profile),
-            kTargetPlatform: getNameForTargetPlatform(TargetPlatform.ios),
-          }
-        );
-        buildSystem = BuildSystem();
-        HostPlatform hostPlatform;
-        if (platform.isWindows) {
-          hostPlatform = HostPlatform.windows_x64;
-        } else if (platform.isLinux) {
-          hostPlatform = HostPlatform.linux_x64;
-        } else if (platform.isMacOS) {
-           hostPlatform = HostPlatform.darwin_x64;
-        } else {
-          assert(false);
         }
-         final String skyEngineLine = platform.isWindows
+      );
-            ? r'sky_engine:file:///C:/bin/cache/pkg/sky_engine/lib/'
+      iosEnvironment = Environment(
-            : 'sky_engine:file:///bin/cache/pkg/sky_engine/lib/';
+        projectDir: fs.currentDirectory,
-        fs.file('.packages')
+        defines: <String, String>{
-          ..createSync()
+          kBuildMode: getNameForBuildMode(BuildMode.profile),
-          ..writeAsStringSync('''
+          kTargetPlatform: getNameForTargetPlatform(TargetPlatform.ios),
+        }
+      );
+      HostPlatform hostPlatform;
+      if (platform.isWindows) {
+        hostPlatform = HostPlatform.windows_x64;
+      } else if (platform.isLinux) {
+        hostPlatform = HostPlatform.linux_x64;
+      } else if (platform.isMacOS) {
+          hostPlatform = HostPlatform.darwin_x64;
+      } else {
+        assert(false);
+      }
+        final String skyEngineLine = platform.isWindows
+          ? r'sky_engine:file:///C:/bin/cache/pkg/sky_engine/lib/'
+          : 'sky_engine:file:///bin/cache/pkg/sky_engine/lib/';
+      fs.file('.packages')
+        ..createSync()
+        ..writeAsStringSync('''
 # Generated
 $skyEngineLine
 flutter_tools:lib/''');
-        final String engineArtifacts = fs.path.join('bin', 'cache',
+      final String engineArtifacts = fs.path.join('bin', 'cache',
-            'artifacts', 'engine');
+          'artifacts', 'engine');
-        final List<String> paths = <String>[
+      final List<String> paths = <String>[
-          fs.path.join('bin', 'cache', 'pkg', 'sky_engine', 'lib', 'ui',
+        fs.path.join('bin', 'cache', 'pkg', 'sky_engine', 'lib', 'ui',
-            'ui.dart'),
+          'ui.dart'),
-          fs.path.join('bin', 'cache', 'pkg', 'sky_engine', 'sdk_ext',
+        fs.path.join('bin', 'cache', 'pkg', 'sky_engine', 'sdk_ext',
-              'vmservice_io.dart'),
+            'vmservice_io.dart'),
-          fs.path.join('bin', 'cache', 'dart-sdk', 'bin', 'dart'),
+        fs.path.join('bin', 'cache', 'dart-sdk', 'bin', 'dart'),
-          fs.path.join(engineArtifacts, getNameForHostPlatform(hostPlatform),
+        fs.path.join(engineArtifacts, getNameForHostPlatform(hostPlatform),
-              'frontend_server.dart.snapshot'),
+            'frontend_server.dart.snapshot'),
-          fs.path.join(engineArtifacts, 'android-arm-profile',
+        fs.path.join(engineArtifacts, 'android-arm-profile',
-              getNameForHostPlatform(hostPlatform), 'gen_snapshot'),
+            getNameForHostPlatform(hostPlatform), 'gen_snapshot'),
-          fs.path.join(engineArtifacts, 'ios-profile', 'gen_snapshot'),
+        fs.path.join(engineArtifacts, 'ios-profile', 'gen_snapshot'),
-          fs.path.join(engineArtifacts, 'common', 'flutter_patched_sdk',
+        fs.path.join(engineArtifacts, 'common', 'flutter_patched_sdk',
-              'platform_strong.dill'),
+            'platform_strong.dill'),
-          fs.path.join('lib', 'foo.dart'),
+        fs.path.join('lib', 'foo.dart'),
-          fs.path.join('lib', 'bar.dart'),
+        fs.path.join('lib', 'bar.dart'),
-          fs.path.join('lib', 'fizz'),
+        fs.path.join('lib', 'fizz'),
-        ];
+        fs.path.join('packages', 'flutter_tools', 'lib', 'src', 'build_system', 'targets', 'dart.dart'),
-        for (String path in paths) {
+        fs.path.join('packages', 'flutter_tools', 'lib', 'src', 'build_system', 'targets', 'ios.dart'),
-          fs.file(path).createSync(recursive: true);
+      ];
-        }
+      for (String path in paths) {
-      }, overrides: <Type, Generator>{
+        fs.file(path).createSync(recursive: true);
-        KernelCompilerFactory: () => FakeKernelCompilerFactory(),
+      }
-        GenSnapshot: () => FakeGenSnapshot(),
+    }, overrides: <Type, Generator>{
-      });
+      KernelCompilerFactory: () => FakeKernelCompilerFactory(),
+      GenSnapshot: () => FakeGenSnapshot(),
+    });
+  });
+
+  test('kernel_snapshot Produces correct output directory', () => testbed.run(() async {
+    await buildSystem.build(const KernelSnapshot(), androidEnvironment);
+
+    expect(fs.file(fs.path.join(androidEnvironment.buildDir.path,'app.dill')).existsSync(), true);
+  }));
+
+  test('kernel_snapshot throws error if missing build mode', () => testbed.run(() async {
+    final BuildResult result = await buildSystem.build(const KernelSnapshot(),
+        androidEnvironment..defines.remove(kBuildMode));
+
+    expect(result.exceptions.values.single.exception, isInstanceOf<MissingDefineException>());
+  }));
+
+  test('aot_elf_profile Produces correct output directory', () => testbed.run(() async {
+    await buildSystem.build(const AotElfProfile(), androidEnvironment);
+
+    expect(fs.file(fs.path.join(androidEnvironment.buildDir.path, 'app.dill')).existsSync(), true);
+    expect(fs.file(fs.path.join(androidEnvironment.buildDir.path, 'app.so')).existsSync(), true);
+  }));
+
+  test('aot_elf_profile throws error if missing build mode', () => testbed.run(() async {
+    final BuildResult result = await buildSystem.build(const AotElfProfile(),
+        androidEnvironment..defines.remove(kBuildMode));
+
+    expect(result.exceptions.values.single.exception, isInstanceOf<MissingDefineException>());
+  }));
+
+
+  test('aot_elf_profile throws error if missing target platform', () => testbed.run(() async {
+    final BuildResult result = await buildSystem.build(const AotElfProfile(),
+        androidEnvironment..defines.remove(kTargetPlatform));
+
+    expect(result.exceptions.values.single.exception, isInstanceOf<MissingDefineException>());
+  }));
+
+
+  test('aot_assembly_profile throws error if missing build mode', () => testbed.run(() async {
+    final BuildResult result = await buildSystem.build(const AotAssemblyProfile(),
+        iosEnvironment..defines.remove(kBuildMode));
+
+    expect(result.exceptions.values.single.exception, isInstanceOf<MissingDefineException>());
+  }));
+
+  test('aot_assembly_profile throws error if missing target platform', () => testbed.run(() async {
+    final BuildResult result = await buildSystem.build(const AotAssemblyProfile(),
+        iosEnvironment..defines.remove(kTargetPlatform));
+
+    expect(result.exceptions.values.single.exception, isInstanceOf<MissingDefineException>());
+  }));
+
+  test('aot_assembly_profile throws error if built for non-iOS platform', () => testbed.run(() async {
+    final BuildResult result = await buildSystem
+        .build(const AotAssemblyProfile(), androidEnvironment);
+
+    expect(result.exceptions.values.single.exception, isInstanceOf<Exception>());
+  }));
+
+  test('aot_assembly_profile will lipo binaries together when multiple archs are requested', () => testbed.run(() async {
+    iosEnvironment.defines[kIosArchs] ='armv7,arm64';
+    when(mockProcessManager.run(any)).thenAnswer((Invocation invocation) async {
+      fs.file(fs.path.join(iosEnvironment.buildDir.path, 'App.framework', 'App'))
+          .createSync(recursive: true);
+      return FakeProcessResult(
+        stdout: '',
+        stderr: '',
+      );
+    });
+    final BuildResult result = await buildSystem
+        .build(const AotAssemblyProfile(), iosEnvironment);
+    expect(result.success, true);
+  }, overrides: <Type, Generator>{
+    ProcessManager: () => mockProcessManager,
+  }));
+
+  test('aot_assembly_profile with bitcode sends correct argument to snapshotter (one arch)', () => testbed.run(() async {
+    iosEnvironment.defines[kIosArchs] = 'arm64';
+    iosEnvironment.defines[kBitcodeFlag] = 'true';
+
+    final FakeProcessResult fakeProcessResult = FakeProcessResult(
+      stdout: '',
+      stderr: '',
+    );
+    final RunResult fakeRunResult = RunResult(fakeProcessResult, const <String>['foo']);
+    when(mockProcessManager.run(any)).thenAnswer((Invocation invocation) async {
+      fs.file(fs.path.join(iosEnvironment.buildDir.path, 'App.framework', 'App'))
+          .createSync(recursive: true);
+      return fakeProcessResult;
     });
 
-    test('kernel_snapshot Produces correct output directory', () => testbed.run(() async {
+    when(mockXcode.cc(any)).thenAnswer((_) => Future<RunResult>.value(fakeRunResult));
-      await buildSystem.build('kernel_snapshot', androidEnvironment, const BuildSystemConfig());
+    when(mockXcode.clang(any)).thenAnswer((_) => Future<RunResult>.value(fakeRunResult));
+    when(mockXcode.dsymutil(any)).thenAnswer((_) => Future<RunResult>.value(fakeRunResult));
 
-      expect(fs.file(fs.path.join(androidEnvironment.buildDir.path,'main.app.dill')).existsSync(), true);
+    final BuildResult result = await buildSystem.build(const AotAssemblyProfile(), iosEnvironment);
-    }));
 
-    test('kernel_snapshot throws error if missing build mode', () => testbed.run(() async {
+    expect(result.success, true);
-      final BuildResult result = await buildSystem.build('kernel_snapshot',
+    verify(mockXcode.cc(argThat(contains('-fembed-bitcode')))).called(1);
-          androidEnvironment..defines.remove(kBuildMode), const BuildSystemConfig());
+    verify(mockXcode.clang(argThat(contains('-fembed-bitcode')))).called(1);
+    verify(mockXcode.dsymutil(any)).called(1);
+  }, overrides: <Type, Generator>{
+    ProcessManager: () => mockProcessManager,
+    Xcode: () => mockXcode,
+  }));
 
-      expect(result.exceptions.values.single.exception, isInstanceOf<MissingDefineException>());
+  test('aot_assembly_profile with bitcode sends correct argument to snapshotter (mutli arch)', () => testbed.run(() async {
-    }));
+    iosEnvironment.defines[kIosArchs] = 'armv7,arm64';
+    iosEnvironment.defines[kBitcodeFlag] = 'true';
 
-    test('aot_elf_profile Produces correct output directory', () => testbed.run(() async {
+    final FakeProcessResult fakeProcessResult = FakeProcessResult(
-      await buildSystem.build('aot_elf_profile', androidEnvironment, const BuildSystemConfig());
+      stdout: '',
+      stderr: '',
+    );
+    final RunResult fakeRunResult = RunResult(fakeProcessResult, const <String>['foo']);
+    when(mockProcessManager.run(any)).thenAnswer((Invocation invocation) async {
+      fs.file(fs.path.join(iosEnvironment.buildDir.path, 'App.framework', 'App'))
+          .createSync(recursive: true);
+      return fakeProcessResult;
+    });
 
-      expect(fs.file(fs.path.join(androidEnvironment.buildDir.path, 'main.app.dill')).existsSync(), true);
+    when(mockXcode.cc(any)).thenAnswer((_) => Future<RunResult>.value(fakeRunResult));
-      expect(fs.file(fs.path.join(androidEnvironment.buildDir.path, 'app.so')).existsSync(), true);
+    when(mockXcode.clang(any)).thenAnswer((_) => Future<RunResult>.value(fakeRunResult));
-    }));
+    when(mockXcode.dsymutil(any)).thenAnswer((_) => Future<RunResult>.value(fakeRunResult));
 
-    test('aot_elf_profile throws error if missing build mode', () => testbed.run(() async {
+    final BuildResult result = await buildSystem.build(const AotAssemblyProfile(), iosEnvironment);
-      final BuildResult result = await buildSystem.build('aot_elf_profile',
-          androidEnvironment..defines.remove(kBuildMode), const BuildSystemConfig());
 
-      expect(result.exceptions.values.single.exception, isInstanceOf<MissingDefineException>());
+    expect(result.success, true);
-    }));
+    verify(mockXcode.cc(argThat(contains('-fembed-bitcode')))).called(2);
+    verify(mockXcode.clang(argThat(contains('-fembed-bitcode')))).called(2);
+    verify(mockXcode.dsymutil(any)).called(2);
+  }, overrides: <Type, Generator>{
+    ProcessManager: () => mockProcessManager,
+    Xcode: () => mockXcode,
+  }));
 
-
+  test('aot_assembly_profile will lipo binaries together when multiple archs are requested', () => testbed.run(() async {
-    test('aot_elf_profile throws error if missing target platform', () => testbed.run(() async {
+    iosEnvironment.defines[kIosArchs] = 'armv7,arm64';
-      final BuildResult result = await buildSystem.build('aot_elf_profile',
+    when(mockProcessManager.run(any)).thenAnswer((Invocation invocation) async {
-          androidEnvironment..defines.remove(kTargetPlatform), const BuildSystemConfig());
+      fs.file(fs.path.join(iosEnvironment.buildDir.path, 'App.framework', 'App'))
-
+          .createSync(recursive: true);
-      expect(result.exceptions.values.single.exception, isInstanceOf<MissingDefineException>());
+      return FakeProcessResult(
-    }));
-
-
-    test('aot_assembly_profile throws error if missing build mode', () => testbed.run(() async {
-      final BuildResult result = await buildSystem.build('aot_assembly_profile',
-          iosEnvironment..defines.remove(kBuildMode), const BuildSystemConfig());
-
-      expect(result.exceptions.values.single.exception, isInstanceOf<MissingDefineException>());
-    }));
-
-    test('aot_assembly_profile throws error if missing target platform', () => testbed.run(() async {
-      final BuildResult result = await buildSystem.build('aot_assembly_profile',
-          iosEnvironment..defines.remove(kTargetPlatform), const BuildSystemConfig());
-
-      expect(result.exceptions.values.single.exception, isInstanceOf<MissingDefineException>());
-    }));
-
-    test('aot_assembly_profile throws error if built for non-iOS platform', () => testbed.run(() async {
-      final BuildResult result = await buildSystem.build('aot_assembly_profile',
-          androidEnvironment, const BuildSystemConfig());
-
-      expect(result.exceptions.values.single.exception, isInstanceOf<Exception>());
-    }));
-
-    test('aot_assembly_profile with bitcode sends correct argument to snapshotter (one arch)', () => testbed.run(() async {
-      iosEnvironment.defines[kIosArchs] = 'arm64';
-      iosEnvironment.defines[kBitcodeFlag] = 'true';
-
-      final FakeProcessResult fakeProcessResult = FakeProcessResult(
         stdout: '',
         stderr: '',
       );
-      final RunResult fakeRunResult = RunResult(fakeProcessResult, const <String>['foo']);
+    });
-      when(mockProcessManager.run(any)).thenAnswer((Invocation invocation) async {
+    final BuildResult result = await buildSystem.build(const AotAssemblyProfile(), iosEnvironment);
-        fs.file(fs.path.join(iosEnvironment.buildDir.path, 'App.framework', 'App'))
-            .createSync(recursive: true);
-        return fakeProcessResult;
-      });
 
-      when(mockXcode.cc(any)).thenAnswer((_) => Future<RunResult>.value(fakeRunResult));
+    expect(result.success, true);
-      when(mockXcode.clang(any)).thenAnswer((_) => Future<RunResult>.value(fakeRunResult));
+  }, overrides: <Type, Generator>{
-      when(mockXcode.dsymutil(any)).thenAnswer((_) => Future<RunResult>.value(fakeRunResult));
+    ProcessManager: () => mockProcessManager,
-
+  }));
-      final BuildResult result = await buildSystem.build('aot_assembly_profile',
-          iosEnvironment, const BuildSystemConfig());
-
-      expect(result.success, true);
-      verify(mockXcode.cc(argThat(contains('-fembed-bitcode')))).called(1);
-      verify(mockXcode.clang(argThat(contains('-fembed-bitcode')))).called(1);
-      verify(mockXcode.dsymutil(any)).called(1);
-    }, overrides: <Type, Generator>{
-      ProcessManager: () => mockProcessManager,
-      Xcode: () => mockXcode,
-    }));
-
-    test('aot_assembly_profile with bitcode sends correct argument to snapshotter (mutli arch)', () => testbed.run(() async {
-      iosEnvironment.defines[kIosArchs] = 'armv7,arm64';
-      iosEnvironment.defines[kBitcodeFlag] = 'true';
-
-      final FakeProcessResult fakeProcessResult = FakeProcessResult(
-        stdout: '',
-        stderr: '',
-      );
-      final RunResult fakeRunResult = RunResult(fakeProcessResult, const <String>['foo']);
-      when(mockProcessManager.run(any)).thenAnswer((Invocation invocation) async {
-        fs.file(fs.path.join(iosEnvironment.buildDir.path, 'App.framework', 'App'))
-            .createSync(recursive: true);
-        return fakeProcessResult;
-      });
-
-      when(mockXcode.cc(any)).thenAnswer((_) => Future<RunResult>.value(fakeRunResult));
-      when(mockXcode.clang(any)).thenAnswer((_) => Future<RunResult>.value(fakeRunResult));
-      when(mockXcode.dsymutil(any)).thenAnswer((_) => Future<RunResult>.value(fakeRunResult));
-
-      final BuildResult result = await buildSystem.build('aot_assembly_profile',
-          iosEnvironment, const BuildSystemConfig());
-
-      expect(result.success, true);
-      verify(mockXcode.cc(argThat(contains('-fembed-bitcode')))).called(2);
-      verify(mockXcode.clang(argThat(contains('-fembed-bitcode')))).called(2);
-      verify(mockXcode.dsymutil(any)).called(2);
-    }, overrides: <Type, Generator>{
-      ProcessManager: () => mockProcessManager,
-      Xcode: () => mockXcode,
-    }));
-
-    test('aot_assembly_profile will lipo binaries together when multiple archs are requested', () => testbed.run(() async {
-      iosEnvironment.defines[kIosArchs] = 'armv7,arm64';
-      when(mockProcessManager.run(any)).thenAnswer((Invocation invocation) async {
-        fs.file(fs.path.join(iosEnvironment.buildDir.path, 'App.framework', 'App'))
-            .createSync(recursive: true);
-        return FakeProcessResult(
-          stdout: '',
-          stderr: '',
-        );
-      });
-      final BuildResult result = await buildSystem.build('aot_assembly_profile',
-          iosEnvironment, const BuildSystemConfig());
-
-      expect(result.success, true);
-    }, overrides: <Type, Generator>{
-      ProcessManager: () => mockProcessManager,
-    }));
-  });
 }
 
 class MockProcessManager extends Mock implements ProcessManager {}

packages/flutter_tools/test/general.shard/build_system/targets/linux_test.dart

@@ -13,72 +13,72 @@ import '../../../src/common.dart';
 import '../../../src/testbed.dart';
 
 void main() {
-  group('unpack_linux', () {
+  Testbed testbed;
-    Testbed testbed;
+  const BuildSystem buildSystem = BuildSystem();
-    BuildSystem buildSystem;
+  Environment environment;
-    Environment environment;
+  MockPlatform mockPlatform;
-    MockPlatform mockPlatform;
 
-    setUpAll(() {
+  setUpAll(() {
-      Cache.disableLocking();
+    Cache.disableLocking();
-    });
+    Cache.flutterRoot = '';
-
-    setUp(() {
-      mockPlatform = MockPlatform();
-      when(mockPlatform.isWindows).thenReturn(false);
-      when(mockPlatform.isMacOS).thenReturn(false);
-      when(mockPlatform.isLinux).thenReturn(true);
-      testbed = Testbed(setup: () {
-        Cache.flutterRoot = '';
-        environment = Environment(
-          projectDir: fs.currentDirectory,
-        );
-        buildSystem = BuildSystem(<String, Target>{
-          unpackLinux.name: unpackLinux,
-        });
-        fs.file('bin/cache/artifacts/engine/linux-x64/libflutter_linux.so').createSync(recursive: true);
-        fs.file('bin/cache/artifacts/engine/linux-x64/flutter_export.h').createSync();
-        fs.file('bin/cache/artifacts/engine/linux-x64/flutter_messenger.h').createSync();
-        fs.file('bin/cache/artifacts/engine/linux-x64/flutter_plugin_registrar.h').createSync();
-        fs.file('bin/cache/artifacts/engine/linux-x64/flutter_glfw.h').createSync();
-        fs.file('bin/cache/artifacts/engine/linux-x64/icudtl.dat').createSync();
-        fs.file('bin/cache/artifacts/engine/linux-x64/cpp_client_wrapper/foo').createSync(recursive: true);
-        fs.directory('linux').createSync();
-      }, overrides: <Type, Generator>{
-        Platform: () => mockPlatform,
-      });
-    });
-
-    test('Copies files to correct cache directory', () => testbed.run(() async {
-      final BuildResult result = await buildSystem.build('unpack_linux', environment, const BuildSystemConfig());
-
-      expect(result.hasException, false);
-      expect(fs.file('linux/flutter/libflutter_linux.so').existsSync(), true);
-      expect(fs.file('linux/flutter/flutter_export.h').existsSync(), true);
-      expect(fs.file('linux/flutter/flutter_messenger.h').existsSync(), true);
-      expect(fs.file('linux/flutter/flutter_plugin_registrar.h').existsSync(), true);
-      expect(fs.file('linux/flutter/flutter_glfw.h').existsSync(), true);
-      expect(fs.file('linux/flutter/icudtl.dat').existsSync(), true);
-      expect(fs.file('linux/flutter/cpp_client_wrapper/foo').existsSync(), true);
-    }));
-
-    test('Does not re-copy files unecessarily', () => testbed.run(() async {
-      await buildSystem.build('unpack_linux', environment, const BuildSystemConfig());
-      final DateTime modified = fs.file('linux/flutter/libflutter_linux.so').statSync().modified;
-      await buildSystem.build('unpack_linux', environment, const BuildSystemConfig());
-
-      expect(fs.file('linux/flutter/libflutter_linux.so').statSync().modified, equals(modified));
-    }));
-
-    test('Detects changes in input cache files', () => testbed.run(() async {
-      await buildSystem.build('unpack_linux', environment, const BuildSystemConfig());
-      fs.file('bin/cache/artifacts/engine/linux-x64/libflutter_linux.so').writeAsStringSync('asd'); // modify cache.
-
-      await buildSystem.build('unpack_linux', environment, const BuildSystemConfig());
-
-      expect(fs.file('linux/flutter/libflutter_linux.so').readAsStringSync(), 'asd');
-    }));
   });
+
+  setUp(() {
+    mockPlatform = MockPlatform();
+    when(mockPlatform.isWindows).thenReturn(false);
+    when(mockPlatform.isMacOS).thenReturn(false);
+    when(mockPlatform.isLinux).thenReturn(true);
+    testbed = Testbed(setup: () {
+      Cache.flutterRoot = '';
+      environment = Environment(
+        projectDir: fs.currentDirectory,
+      );
+      fs.file('bin/cache/artifacts/engine/linux-x64/libflutter_linux.so').createSync(recursive: true);
+      fs.file('bin/cache/artifacts/engine/linux-x64/flutter_export.h').createSync();
+      fs.file('bin/cache/artifacts/engine/linux-x64/flutter_messenger.h').createSync();
+      fs.file('bin/cache/artifacts/engine/linux-x64/flutter_plugin_registrar.h').createSync();
+      fs.file('bin/cache/artifacts/engine/linux-x64/flutter_glfw.h').createSync();
+      fs.file('bin/cache/artifacts/engine/linux-x64/icudtl.dat').createSync();
+      fs.file('bin/cache/artifacts/engine/linux-x64/cpp_client_wrapper/foo').createSync(recursive: true);
+      fs.file('packages/flutter_tools/lib/src/build_system/targets/linux.dart').createSync(recursive: true);
+      fs.directory('linux').createSync();
+    }, overrides: <Type, Generator>{
+      Platform: () => mockPlatform,
+    });
+  });
+
+  test('Copies files to correct cache directory', () => testbed.run(() async {
+    final BuildResult result = await buildSystem.build(const UnpackLinux(), environment);
+
+    expect(result.hasException, false);
+    expect(fs.file('linux/flutter/libflutter_linux.so').existsSync(), true);
+    expect(fs.file('linux/flutter/flutter_export.h').existsSync(), true);
+    expect(fs.file('linux/flutter/flutter_messenger.h').existsSync(), true);
+    expect(fs.file('linux/flutter/flutter_plugin_registrar.h').existsSync(), true);
+    expect(fs.file('linux/flutter/flutter_glfw.h').existsSync(), true);
+    expect(fs.file('linux/flutter/icudtl.dat').existsSync(), true);
+    expect(fs.file('linux/flutter/cpp_client_wrapper/foo').existsSync(), true);
+  }));
+
+  test('Does not re-copy files unecessarily', () => testbed.run(() async {
+    await buildSystem.build(const UnpackLinux(), environment);
+    // Set a date in the far distant past to deal with the limited resolution
+    // of the windows filesystem.
+    final DateTime theDistantPast = DateTime(1991, 8, 23);
+    fs.file('linux/flutter/libflutter_linux.so').setLastModifiedSync(theDistantPast);
+    await buildSystem.build(const UnpackLinux(), environment);
+
+    expect(fs.file('linux/flutter/libflutter_linux.so').statSync().modified, equals(theDistantPast));
+  }));
+
+  test('Detects changes in input cache files', () => testbed.run(() async {
+    await buildSystem.build(const UnpackLinux(), environment);
+    fs.file('bin/cache/artifacts/engine/linux-x64/libflutter_linux.so').writeAsStringSync('asd'); // modify cache.
+
+    await buildSystem.build(const UnpackLinux(), environment);
+
+    expect(fs.file('linux/flutter/libflutter_linux.so').readAsStringSync(), 'asd');
+  }));
 }
 
 class MockPlatform extends Mock implements Platform {}

packages/flutter_tools/test/general.shard/build_system/targets/macos_test.dart

@@ -8,6 +8,7 @@ import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/base/process_manager.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/build_system/targets/macos.dart';
+import 'package:flutter_tools/src/cache.dart';
 import 'package:mockito/mockito.dart';
 import 'package:process/process.dart';
 
@@ -15,86 +16,87 @@ import '../../../src/common.dart';
 import '../../../src/testbed.dart';
 
 void main() {
-  group('unpack_macos', () {
+  Testbed testbed;
-    Testbed testbed;
+  const BuildSystem buildSystem = BuildSystem();
-    BuildSystem buildSystem;
+  Environment environment;
-    Environment environment;
+  MockPlatform mockPlatform;
-    MockPlatform mockPlatform;
 
-    setUp(() {
+  setUpAll(() {
-      mockPlatform = MockPlatform();
+    Cache.disableLocking();
-      when(mockPlatform.isWindows).thenReturn(false);
+    Cache.flutterRoot = '';
-      when(mockPlatform.isMacOS).thenReturn(true);
-      when(mockPlatform.isLinux).thenReturn(false);
-      testbed = Testbed(setup: () {
-        environment = Environment(
-          projectDir: fs.currentDirectory,
-        );
-        buildSystem = BuildSystem(<String, Target>{
-          unpackMacos.name: unpackMacos,
-        });
-        final List<File> inputs = <File>[
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/FlutterMacOS'),
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FLEOpenGLContextHandling.h'),
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FLEReshapeListener.h'),
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FLEView.h'),
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FLEViewController.h'),
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FlutterBinaryMessenger.h'),
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FlutterChannels.h'),
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FlutterCodecs.h'),
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FlutterMacOS.h'),
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FlutterPluginMacOS.h'),
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FlutterPluginRegisrarMacOS.h'),
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Modules/module.modulemap'),
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Resources/icudtl.dat'),
-          fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Resources/info.plist'),
-        ];
-        for (File input in inputs) {
-          input.createSync(recursive: true);
-        }
-        when(processManager.runSync(any)).thenAnswer((Invocation invocation) {
-          final List<String> arguments = invocation.positionalArguments.first;
-          final Directory source = fs.directory(arguments[arguments.length - 2]);
-          final Directory target = fs.directory(arguments.last)
-            ..createSync(recursive: true);
-          for (FileSystemEntity entity in source.listSync(recursive: true)) {
-            if (entity is File) {
-              final String relative = fs.path.relative(entity.path, from: source.path);
-              final String destination = fs.path.join(target.path, relative);
-              if (!fs.file(destination).parent.existsSync()) {
-                fs.file(destination).parent.createSync();
-              }
-              entity.copySync(destination);
-            }
-          }
-          return FakeProcessResult()..exitCode = 0;
-        });
-      }, overrides: <Type, Generator>{
-        ProcessManager: () => MockProcessManager(),
-        Platform: () => mockPlatform,
-      });
-    });
-
-    test('Copies files to correct cache directory', () => testbed.run(() async {
-      await buildSystem.build('unpack_macos', environment, const BuildSystemConfig());
-
-      expect(fs.directory('macos/Flutter/FlutterMacOS.framework').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/FlutterMacOS').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FLEOpenGLContextHandling.h').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FLEReshapeListener.h').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FLEView.h').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FLEViewController.h').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FlutterBinaryMessenger.h').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FlutterChannels.h').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FlutterCodecs.h').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FlutterMacOS.h').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FlutterPluginMacOS.h').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FlutterPluginRegisrarMacOS.h').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/Modules/module.modulemap').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/Resources/icudtl.dat').existsSync(), true);
-      expect(fs.file('macos/Flutter/FlutterMacOS.framework/Resources/info.plist').existsSync(), true);
-    }));
   });
+
+  setUp(() {
+    mockPlatform = MockPlatform();
+    when(mockPlatform.isWindows).thenReturn(false);
+    when(mockPlatform.isMacOS).thenReturn(true);
+    when(mockPlatform.isLinux).thenReturn(false);
+    testbed = Testbed(setup: () {
+      environment = Environment(
+        projectDir: fs.currentDirectory,
+      );
+      final List<File> inputs = <File>[
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/FlutterMacOS'),
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FLEOpenGLContextHandling.h'),
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FLEReshapeListener.h'),
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FLEView.h'),
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FLEViewController.h'),
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FlutterBinaryMessenger.h'),
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FlutterChannels.h'),
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FlutterCodecs.h'),
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FlutterMacOS.h'),
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FlutterPluginMacOS.h'),
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Headers/FlutterPluginRegisrarMacOS.h'),
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Modules/module.modulemap'),
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Resources/icudtl.dat'),
+        fs.file('bin/cache/artifacts/engine/darwin-x64/FlutterMacOS.framework/Resources/info.plist'),
+        fs.file('packages/flutter_tools/lib/src/build_system/targets/macos.dart'),
+      ];
+      for (File input in inputs) {
+        input.createSync(recursive: true);
+      }
+      when(processManager.run(any)).thenAnswer((Invocation invocation) async {
+        final List<String> arguments = invocation.positionalArguments.first;
+        final Directory source = fs.directory(arguments[arguments.length - 2]);
+        final Directory target = fs.directory(arguments.last)
+          ..createSync(recursive: true);
+        for (FileSystemEntity entity in source.listSync(recursive: true)) {
+          if (entity is File) {
+            final String relative = fs.path.relative(entity.path, from: source.path);
+            final String destination = fs.path.join(target.path, relative);
+            if (!fs.file(destination).parent.existsSync()) {
+              fs.file(destination).parent.createSync();
+            }
+            entity.copySync(destination);
+          }
+        }
+        return FakeProcessResult()..exitCode = 0;
+      });
+    }, overrides: <Type, Generator>{
+      ProcessManager: () => MockProcessManager(),
+      Platform: () => mockPlatform,
+    });
+  });
+
+  test('Copies files to correct cache directory', () => testbed.run(() async {
+    await buildSystem.build(const UnpackMacOS(), environment);
+
+    expect(fs.directory('macos/Flutter/FlutterMacOS.framework').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/FlutterMacOS').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FLEOpenGLContextHandling.h').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FLEReshapeListener.h').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FLEView.h').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FLEViewController.h').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FlutterBinaryMessenger.h').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FlutterChannels.h').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FlutterCodecs.h').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FlutterMacOS.h').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FlutterPluginMacOS.h').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/Headers/FlutterPluginRegisrarMacOS.h').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/Modules/module.modulemap').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/Resources/icudtl.dat').existsSync(), true);
+    expect(fs.file('macos/Flutter/FlutterMacOS.framework/Resources/info.plist').existsSync(), true);
+  }));
 }
 
 class MockPlatform extends Mock implements Platform {}

packages/flutter_tools/test/general.shard/build_system/targets/windows_test.dart

@@ -14,84 +14,87 @@ import '../../../src/common.dart';
 import '../../../src/testbed.dart';
 
 void main() {
-  group('unpack_windows', () {
+  Testbed testbed;
-    Testbed testbed;
+  const BuildSystem buildSystem = BuildSystem();
-    BuildSystem buildSystem;
+  Environment environment;
-    Environment environment;
+  Platform platform;
-    Platform platform;
 
-    setUpAll(() {
+  setUpAll(() {
-      Cache.disableLocking();
+    Cache.disableLocking();
-    });
+    Cache.flutterRoot = '';
-
-    setUp(() {
-      Cache.flutterRoot = '';
-      platform = MockPlatform();
-      when(platform.isWindows).thenReturn(true);
-      when(platform.isMacOS).thenReturn(false);
-      when(platform.isLinux).thenReturn(false);
-      when(platform.pathSeparator).thenReturn(r'\');
-      testbed = Testbed(setup: () {
-        environment = Environment(
-          projectDir: fs.currentDirectory,
-        );
-        buildSystem = BuildSystem(<String, Target>{
-          unpackWindows.name: unpackWindows,
-        });
-        fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_export.h').createSync(recursive: true);
-        fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_messenger.h').createSync();
-        fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_windows.dll').createSync();
-        fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_windows.dll.exp').createSync();
-        fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_windows.dll.lib').createSync();
-        fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_windows.dll.pdb').createSync();
-        fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\lutter_export.h').createSync();
-        fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_messenger.h').createSync();
-        fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_plugin_registrar.h').createSync();
-        fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_glfw.h').createSync();
-        fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\icudtl.dat').createSync();
-        fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\cpp_client_wrapper\foo').createSync(recursive: true);
-        fs.directory('windows').createSync();
-      }, overrides: <Type, Generator>{
-        FileSystem: () => MemoryFileSystem(style: FileSystemStyle.windows),
-        Platform: () => platform,
-      });
-    });
-
-    test('Copies files to correct cache directory', () => testbed.run(() async {
-      await buildSystem.build('unpack_windows', environment, const BuildSystemConfig());
-
-      expect(fs.file(r'C:\windows\flutter\flutter_export.h').existsSync(), true);
-      expect(fs.file(r'C:\windows\flutter\flutter_messenger.h').existsSync(), true);
-      expect(fs.file(r'C:\windows\flutter\flutter_windows.dll').existsSync(), true);
-      expect(fs.file(r'C:\windows\flutter\flutter_windows.dll.exp').existsSync(), true);
-      expect(fs.file(r'C:\windows\flutter\flutter_windows.dll.lib').existsSync(), true);
-      expect(fs.file(r'C:\windows\flutter\flutter_windows.dll.pdb').existsSync(), true);
-      expect(fs.file(r'C:\windows\flutter\flutter_export.h').existsSync(), true);
-      expect(fs.file(r'C:\windows\flutter\flutter_messenger.h').existsSync(), true);
-      expect(fs.file(r'C:\windows\flutter\flutter_plugin_registrar.h').existsSync(), true);
-      expect(fs.file(r'C:\windows\flutter\flutter_glfw.h').existsSync(), true);
-      expect(fs.file(r'C:\windows\flutter\icudtl.dat').existsSync(), true);
-      expect(fs.file(r'C:\windows\flutter\cpp_client_wrapper\foo').existsSync(), true);
-    }));
-
-    test('Does not re-copy files unecessarily', () => testbed.run(() async {
-      await buildSystem.build('unpack_windows', environment, const BuildSystemConfig());
-      final DateTime modified = fs.file(r'C:\windows\flutter\flutter_export.h').statSync().modified;
-      await buildSystem.build('unpack_windows', environment, const BuildSystemConfig());
-
-      expect(fs.file(r'C:\windows\flutter\flutter_export.h').statSync().modified, equals(modified));
-    }));
-
-    test('Detects changes in input cache files', () => testbed.run(() async {
-      await buildSystem.build('unpack_windows', environment, const BuildSystemConfig());
-      final DateTime modified = fs.file(r'C:\windows\flutter\flutter_export.h').statSync().modified;
-      fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_export.h').writeAsStringSync('asd'); // modify cache.
-
-      await buildSystem.build('unpack_windows', environment, const BuildSystemConfig());
-
-      expect(fs.file(r'C:\windows\flutter\flutter_export.h').statSync().modified, isNot(modified));
-    }), skip: true); // TODO(jonahwilliams): track down flakiness.
   });
+
+  setUp(() {
+    platform = MockPlatform();
+    when(platform.isWindows).thenReturn(true);
+    when(platform.isMacOS).thenReturn(false);
+    when(platform.isLinux).thenReturn(false);
+    when(platform.pathSeparator).thenReturn(r'\');
+    testbed = Testbed(setup: () {
+      environment = Environment(
+        projectDir: fs.currentDirectory,
+      );
+      fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_export.h').createSync(recursive: true);
+      fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_messenger.h').createSync();
+      fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_windows.dll').createSync();
+      fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_windows.dll.exp').createSync();
+      fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_windows.dll.lib').createSync();
+      fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_windows.dll.pdb').createSync();
+      fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\lutter_export.h').createSync();
+      fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_messenger.h').createSync();
+      fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_plugin_registrar.h').createSync();
+      fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_glfw.h').createSync();
+      fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\icudtl.dat').createSync();
+      fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\cpp_client_wrapper\foo').createSync(recursive: true);
+      fs.file(r'C:\packages\flutter_tools\lib\src\build_system\targets\windows.dart').createSync(recursive: true);
+      fs.directory('windows').createSync();
+    }, overrides: <Type, Generator>{
+      FileSystem: () => MemoryFileSystem(style: FileSystemStyle.windows),
+      Platform: () => platform,
+    });
+  });
+
+  test('Copies files to correct cache directory', () => testbed.run(() async {
+    await buildSystem.build(const UnpackWindows(), environment);
+
+    expect(fs.file(r'C:\windows\flutter\flutter_export.h').existsSync(), true);
+    expect(fs.file(r'C:\windows\flutter\flutter_messenger.h').existsSync(), true);
+    expect(fs.file(r'C:\windows\flutter\flutter_windows.dll').existsSync(), true);
+    expect(fs.file(r'C:\windows\flutter\flutter_windows.dll.exp').existsSync(), true);
+    expect(fs.file(r'C:\windows\flutter\flutter_windows.dll.lib').existsSync(), true);
+    expect(fs.file(r'C:\windows\flutter\flutter_windows.dll.pdb').existsSync(), true);
+    expect(fs.file(r'C:\windows\flutter\flutter_export.h').existsSync(), true);
+    expect(fs.file(r'C:\windows\flutter\flutter_messenger.h').existsSync(), true);
+    expect(fs.file(r'C:\windows\flutter\flutter_plugin_registrar.h').existsSync(), true);
+    expect(fs.file(r'C:\windows\flutter\flutter_glfw.h').existsSync(), true);
+    expect(fs.file(r'C:\windows\flutter\icudtl.dat').existsSync(), true);
+    expect(fs.file(r'C:\windows\flutter\cpp_client_wrapper\foo').existsSync(), true);
+  }));
+
+  test('Does not re-copy files unecessarily', () => testbed.run(() async {
+    await buildSystem.build(const UnpackWindows(), environment);
+    // Set a date in the far distant past to deal with the limited resolution
+    // of the windows filesystem.
+    final DateTime theDistantPast = DateTime(1991, 8, 23);
+    fs.file(r'C:\windows\flutter\flutter_export.h').setLastModifiedSync(theDistantPast);
+    await buildSystem.build(const UnpackWindows(), environment);
+
+    expect(fs.file(r'C:\windows\flutter\flutter_export.h').statSync().modified, equals(theDistantPast));
+  }));
+
+  test('Detects changes in input cache files', () => testbed.run(() async {
+    await buildSystem.build(const UnpackWindows(), environment);
+    // Set a date in the far distant past to deal with the limited resolution
+    // of the windows filesystem.
+    final DateTime theDistantPast = DateTime(1991, 8, 23);
+    fs.file(r'C:\windows\flutter\flutter_export.h').setLastModifiedSync(theDistantPast);
+    final DateTime modified = fs.file(r'C:\windows\flutter\flutter_export.h').statSync().modified;
+    fs.file(r'C:\bin\cache\artifacts\engine\windows-x64\flutter_export.h').writeAsStringSync('asd'); // modify cache.
+
+    await buildSystem.build(const UnpackWindows(), environment);
+
+    expect(fs.file(r'C:\windows\flutter\flutter_export.h').statSync().modified, isNot(modified));
+  }));
 }
 
 class MockPlatform extends Mock implements Platform {}

packages/flutter_tools/test/general.shard/commands/assemble_test.dart

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'package:args/command_runner.dart';
-import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/cache.dart';
@@ -15,68 +14,31 @@ import '../../src/common.dart';
 import '../../src/testbed.dart';
 
 void main() {
-  group('Assemble', () {
+  Testbed testbed;
-    Testbed testbed;
+  MockBuildSystem mockBuildSystem;
-    MockBuildSystem mockBuildSystem;
 
-    setUpAll(() {
+  setUpAll(() {
-      Cache.disableLocking();
+    Cache.disableLocking();
-    });
-
-    setUp(() {
-      mockBuildSystem = MockBuildSystem();
-      testbed = Testbed(overrides: <Type, Generator>{
-        BuildSystem: ()  => mockBuildSystem,
-      });
-    });
-
-    test('Can list the output directory relative to project root', () => testbed.run(() async {
-      final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
-      await commandRunner.run(<String>['assemble', '--flutter-root=.', 'build-dir', '-dBuildMode=debug']);
-      final BufferLogger bufferLogger = logger;
-      final Environment environment = Environment(
-        defines: <String, String>{
-          'BuildMode': 'debug'
-        }, projectDir: fs.currentDirectory,
-        buildDir: fs.directory(fs.path.join('.dart_tool', 'flutter_build')).absolute,
-      );
-
-      expect(bufferLogger.statusText.trim(), environment.buildDir.path);
-    }));
-
-    test('Can describe a target', () => testbed.run(() async {
-      when(mockBuildSystem.describe('foobar', any)).thenReturn(<Map<String, Object>>[
-        <String, Object>{'fizz': 'bar'},
-      ]);
-      final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
-      await commandRunner.run(<String>['assemble', '--flutter-root=.', 'describe', 'foobar']);
-      final BufferLogger bufferLogger = logger;
-
-      expect(bufferLogger.statusText.trim(), '[{"fizz":"bar"}]');
-    }));
-
-    test('Can describe a target\'s inputs', () => testbed.run(() async {
-      when(mockBuildSystem.describe('foobar', any)).thenReturn(<Map<String, Object>>[
-        <String, Object>{'name': 'foobar', 'inputs': <String>['bar', 'baz']},
-      ]);
-      final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
-      await commandRunner.run(<String>['assemble', '--flutter-root=.', 'inputs', 'foobar']);
-      final BufferLogger bufferLogger = logger;
-
-      expect(bufferLogger.statusText.trim(), 'bar\nbaz');
-    }));
-
-    test('Can run a build', () => testbed.run(() async {
-      when(mockBuildSystem.build('foobar', any, any)).thenAnswer((Invocation invocation) async {
-        return BuildResult(true, const <String, ExceptionMeasurement>{}, const <String, PerformanceMeasurement>{});
-      });
-      final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
-      await commandRunner.run(<String>['assemble', 'run', 'foobar']);
-      final BufferLogger bufferLogger = logger;
-
-      expect(bufferLogger.statusText.trim(), 'build succeeded');
-    }));
   });
+
+  setUp(() {
+    mockBuildSystem = MockBuildSystem();
+    testbed = Testbed(overrides: <Type, Generator>{
+      BuildSystem: ()  => mockBuildSystem,
+    });
+  });
+
+  test('Can run a build', () => testbed.run(() async {
+    when(mockBuildSystem.build(any, any, buildSystemConfig: anyNamed('buildSystemConfig')))
+        .thenAnswer((Invocation invocation) async {
+      return BuildResult(true, const <String, ExceptionMeasurement>{}, const <String, PerformanceMeasurement>{});
+    });
+    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
+    await commandRunner.run(<String>['assemble', 'unpack_macos']);
+    final BufferLogger bufferLogger = logger;
+
+    expect(bufferLogger.statusText.trim(), 'build succeeded');
+  }));
 }
 
 class MockBuildSystem extends Mock implements BuildSystem {}