diff --git a/packages/flutter/lib/src/rendering/object.dart b/packages/flutter/lib/src/rendering/object.dart
index 915fdb1bdac..9cda3bf601e 100644
--- a/packages/flutter/lib/src/rendering/object.dart
+++ b/packages/flutter/lib/src/rendering/object.dart
@@ -3196,7 +3196,12 @@ class _RootSemanticsFragment extends _InterestingSemanticsFragment {
     }
     node.updateWith(config: null, childrenInInversePaintOrder: children);
 
-    assert(!node.isInvisible);
+    // The root node is the only semantics node allowed to be invisible. This
+    // can happen when the canvas the app is drawn on has a size of 0 by 0
+    // pixel. If this happens, the root node must not have any children (because
+    // these would be invisible as well and are therefore excluded from the
+    // tree).
+    assert(!node.isInvisible || children.isEmpty);
     yield node;
   }
 
diff --git a/packages/flutter/test/widgets/semantics_zero_surface_size_test.dart b/packages/flutter/test/widgets/semantics_zero_surface_size_test.dart
new file mode 100644
index 00000000000..a7426964560
--- /dev/null
+++ b/packages/flutter/test/widgets/semantics_zero_surface_size_test.dart
@@ -0,0 +1,47 @@
+// Copyright 2018 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/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'semantics_tester.dart';
+
+void main() {
+  testWidgets('has only root node if surface size is 0x0', (WidgetTester tester) async {
+    final SemanticsTester semantics = new SemanticsTester(tester);
+
+    await tester.pumpWidget(new Semantics(
+      selected: true,
+    ));
+
+    expect(semantics, hasSemantics(
+      new TestSemantics(
+        id: 0,
+        rect: new Rect.fromLTRB(0.0, 0.0, 2400.0, 1800.0),
+        children: <TestSemantics>[
+          new TestSemantics(
+            id: 1,
+            rect: new Rect.fromLTRB(0.0, 0.0, 800.0, 600.0),
+            flags: <SemanticsFlag>[SemanticsFlag.isSelected],
+          ),
+        ],
+      ), ignoreTransform: true,
+    ));
+
+    await tester.binding.setSurfaceSize(const Size(0.0, 0.0));
+    await tester.pumpAndSettle();
+
+    expect(semantics, hasSemantics(
+      new TestSemantics(
+        id: 0,
+        rect: new Rect.fromLTRB(0.0, 0.0, 0.0, 0.0),
+      ), ignoreTransform: true,
+    ));
+
+    await tester.binding.setSurfaceSize(null);
+    semantics.dispose();
+  });
+}
diff --git a/packages/flutter_test/lib/src/binding.dart b/packages/flutter_test/lib/src/binding.dart
index a149ceb1052..73859091493 100644
--- a/packages/flutter_test/lib/src/binding.dart
+++ b/packages/flutter_test/lib/src/binding.dart
@@ -235,6 +235,33 @@ abstract class TestWidgetsFlutterBinding extends BindingBase
     });
   }
 
+  Size _surfaceSize;
+
+  /// Artificially changes the surface size to `size` on the Widget binding,
+  /// then flushes microtasks.
+  ///
+  /// Set to null to use the default surface size.
+  Future<Null> setSurfaceSize(Size size) {
+    return TestAsyncUtils.guard(() async {
+      assert(inTest);
+      if (_surfaceSize == size)
+        return null;
+      _surfaceSize = size;
+      handleMetricsChanged();
+      return null;
+    });
+  }
+
+  @override
+  ViewConfiguration createViewConfiguration() {
+    final double devicePixelRatio = ui.window.devicePixelRatio;
+    final Size size = _surfaceSize ?? ui.window.physicalSize / devicePixelRatio;
+    return new ViewConfiguration(
+      size: size,
+      devicePixelRatio: devicePixelRatio,
+    );
+  }
+
   /// Acts as if the application went idle.
   ///
   /// Runs all remaining microtasks, including those scheduled as a result of
@@ -1250,7 +1277,7 @@ class LiveTestWidgetsFlutterBinding extends TestWidgetsFlutterBinding {
 
   @override
   ViewConfiguration createViewConfiguration() {
-    return new TestViewConfiguration();
+    return new TestViewConfiguration(size: _surfaceSize ?? _kDefaultTestViewportSize);
   }
 
   @override