flutter/packages/flutter_tools/templates/module/common/test/widget_test.dart.tmpl

// This is a basic Flutter widget test.
//
// To perform an interaction with a widget in your test, use the WidgetTester
// utility that Flutter provides. For example, you can send tap and scroll
// gestures. You can also use WidgetTester to find child widgets in the widget
// tree, read text, and verify that the values of widget properties are correct.

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';

import 'package:{{projectName}}/main.dart';

{{^withPluginHook}}
void main() {
  testWidgets('Counter increments smoke test', (WidgetTester tester) async {
    // Build our app and trigger a frame.
    await tester.pumpWidget(new MyApp());

    // Verify that our counter starts at 0.
    expect(find.text('0'), findsOneWidget);
    expect(find.text('1'), findsNothing);

    // Tap the '+' icon and trigger a frame.
    await tester.tap(find.byIcon(Icons.add));
    await tester.pump();

    // Verify that our counter has incremented.
    expect(find.text('0'), findsNothing);
    expect(find.text('1'), findsOneWidget);
  });
}
{{/withPluginHook}}
{{#withPluginHook}}
void main() {
  testWidgets('Verify Platform version', (WidgetTester tester) async {
    // Build our app and trigger a frame.
    await tester.pumpWidget(new MyApp());

    // Verify that platform version is retrieved.
    expect(
        find.byWidgetPredicate(
          (Widget widget) =>
              widget is Text && widget.data.startsWith('Running on:'),
        ),
        findsOneWidget);
  });
}
{{/withPluginHook}}