[flutter_tools] replace most MockBuildSystem instances with TestBuildSystem (#76821)

packages/flutter_tools/lib/executable.dart

@@ -144,7 +144,7 @@ List<FlutterCommand> generateCommands({
     terminal: globals.terminal,
     artifacts: globals.artifacts,
   ),
-  AssembleCommand(verboseHelp: verboseHelp),
+  AssembleCommand(verboseHelp: verboseHelp, buildSystem: globals.buildSystem),
   AttachCommand(verboseHelp: verboseHelp),
   BuildCommand(verboseHelp: verboseHelp),
   ChannelCommand(verboseHelp: verboseHelp),

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

@@ -82,7 +82,8 @@ const bool useLegacyNames = true;
 /// Assemble provides a low level API to interact with the flutter tool build
 /// system.
 class AssembleCommand extends FlutterCommand {
-  AssembleCommand({ bool verboseHelp = false }) {
+  AssembleCommand({ bool verboseHelp = false, @required BuildSystem buildSystem })
+    : _buildSystem = buildSystem {
     argParser.addMultiOption(
       'define',
       abbr: 'd',
@@ -124,6 +125,8 @@ class AssembleCommand extends FlutterCommand {
     );
   }
 
+  final BuildSystem _buildSystem;
+
   @override
   String get description => 'Assemble and build Flutter resources.';
 
@@ -229,7 +232,7 @@ class AssembleCommand extends FlutterCommand {
   Future<FlutterCommandResult> runCommand() async {
     final List<Target> targets = createTargets();
     final Target target = targets.length == 1 ? targets.single : CompositeTarget(targets);
-    final BuildResult result = await globals.buildSystem.build(
+    final BuildResult result = await _buildSystem.build(
       target,
       createEnvironment(),
       buildSystemConfig: BuildSystemConfig(

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

@@ -13,99 +13,107 @@ import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/commands/assemble.dart';
 import 'package:flutter_tools/src/convert.dart';
-import 'package:mockito/mockito.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
 
 import '../../src/common.dart';
 import '../../src/context.dart';
+import '../../src/fakes.dart';
 import '../../src/testbed.dart';
 
 void main() {
   Cache.disableLocking();
   Cache.flutterRoot = '';
+  final StackTrace stackTrace = StackTrace.current;
 
-  final Testbed testbed = Testbed(overrides: <Type, Generator>{
+  testUsingContext('flutter assemble can run a build', () async {
-    BuildSystem: ()  => MockBuildSystem(),
+    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand(
-    Cache: () => FakeCache(),
+      buildSystem: TestBuildSystem.all(BuildResult(success: true)),
-  });
+    ));
-
-  testbed.test('flutter assemble can run a build', () async {
-    when(globals.buildSystem.build(any, any, buildSystemConfig: anyNamed('buildSystemConfig')))
-      .thenAnswer((Invocation invocation) async {
-        return BuildResult(success: true);
-      });
-    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
     await commandRunner.run(<String>['assemble', '-o Output', 'debug_macos_bundle_flutter_assets']);
 
     expect(testLogger.traceText, contains('build succeeded.'));
+  }, overrides: <Type, Generator>{
+    Cache: () => FakeCache(),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
-  testbed.test('flutter assemble can parse defines whose values contain =', () async {
+  testUsingContext('flutter assemble can parse defines whose values contain =', () async {
-    when(globals.buildSystem.build(any, any, buildSystemConfig: anyNamed('buildSystemConfig')))
+    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand(
-      .thenAnswer((Invocation invocation) async {
+      buildSystem: TestBuildSystem.all(BuildResult(success: true), (Target target, Environment environment) {
-        expect((invocation.positionalArguments[1] as Environment).defines, containsPair('FooBar', 'fizz=2'));
+        expect(environment.defines, containsPair('FooBar', 'fizz=2'));
-        return BuildResult(success: true);
+      })
-      });
+    ));
-    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
     await commandRunner.run(<String>['assemble', '-o Output', '-dFooBar=fizz=2', 'debug_macos_bundle_flutter_assets']);
 
     expect(testLogger.traceText, contains('build succeeded.'));
+  }, overrides: <Type, Generator>{
+    Cache: () => FakeCache(),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
-  testbed.test('flutter assemble can parse inputs', () async {
+  testUsingContext('flutter assemble can parse inputs', () async {
-    when(globals.buildSystem.build(any, any, buildSystemConfig: anyNamed('buildSystemConfig')))
+    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand(
-      .thenAnswer((Invocation invocation) async {
+      buildSystem: TestBuildSystem.all(BuildResult(success: true), (Target target, Environment environment) {
-        expect((invocation.positionalArguments[1] as Environment).inputs, containsPair('Foo', 'Bar.txt'));
+        expect(environment.inputs, containsPair('Foo', 'Bar.txt'));
-        return BuildResult(success: true);
+      })
-      });
+    ));
-    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
     await commandRunner.run(<String>['assemble', '-o Output', '-iFoo=Bar.txt', 'debug_macos_bundle_flutter_assets']);
 
     expect(testLogger.traceText, contains('build succeeded.'));
+  }, overrides: <Type, Generator>{
+    Cache: () => FakeCache(),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
-  testbed.test('flutter assemble throws ToolExit if not provided with output', () async {
+  testUsingContext('flutter assemble throws ToolExit if not provided with output', () async {
-    when(globals.buildSystem.build(any, any, buildSystemConfig: anyNamed('buildSystemConfig')))
+    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand(
-      .thenAnswer((Invocation invocation) async {
+      buildSystem: TestBuildSystem.all(BuildResult(success: true)),
-        return BuildResult(success: true);
+    ));
-      });
-    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
 
-    expect(commandRunner.run(<String>['assemble', 'debug_macos_bundle_flutter_assets']),
+    expect(commandRunner.run(<String>['assemble', 'debug_macos_bundle_flutter_assets']), throwsToolExit());
-      throwsToolExit());
+  }, overrides: <Type, Generator>{
+    Cache: () => FakeCache(),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
-  testbed.test('flutter assemble throws ToolExit if called with non-existent rule', () async {
+  testUsingContext('flutter assemble throws ToolExit if called with non-existent rule', () async {
-    when(globals.buildSystem.build(any, any, buildSystemConfig: anyNamed('buildSystemConfig')))
+    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand(
-      .thenAnswer((Invocation invocation) async {
+      buildSystem: TestBuildSystem.all(BuildResult(success: true)),
-        return BuildResult(success: true);
+    ));
-      });
-    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
 
     expect(commandRunner.run(<String>['assemble', '-o Output', 'undefined']),
       throwsToolExit());
+  }, overrides: <Type, Generator>{
+    Cache: () => FakeCache(),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
-  testbed.test('flutter assemble does not log stack traces during build failure', () async {
+  testUsingContext('flutter assemble does not log stack traces during build failure', () async {
-    final StackTrace testStackTrace = StackTrace.current;
+    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand(
-    when(globals.buildSystem.build(any, any, buildSystemConfig: anyNamed('buildSystemConfig')))
+      buildSystem: TestBuildSystem.all(BuildResult(success: false, exceptions: <String, ExceptionMeasurement>{
-      .thenAnswer((Invocation invocation) async {
+        'hello': ExceptionMeasurement('hello', 'bar', stackTrace),
-        return BuildResult(success: false, exceptions: <String, ExceptionMeasurement>{
+      }))
-          'hello': ExceptionMeasurement('hello', 'bar', testStackTrace),
+    ));
-        });
-      });
-    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
 
     await expectLater(commandRunner.run(<String>['assemble', '-o Output', 'debug_macos_bundle_flutter_assets']),
       throwsToolExit());
     expect(testLogger.errorText, isNot(contains('bar')));
-    expect(testLogger.errorText, isNot(contains(testStackTrace.toString())));
+    expect(testLogger.errorText, isNot(contains(stackTrace.toString())));
+  }, overrides: <Type, Generator>{
+    Cache: () => FakeCache(),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
-  testbed.test('flutter assemble outputs JSON performance data to provided file', () async {
+  testUsingContext('flutter assemble outputs JSON performance data to provided file', () async {
-    when(globals.buildSystem.build(any, any, buildSystemConfig: anyNamed('buildSystemConfig')))
+    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand(
-      .thenAnswer((Invocation invocation) async {
+      buildSystem: TestBuildSystem.all(
-        return BuildResult(success: true, performance: <String, PerformanceMeasurement>{
+        BuildResult(success: true, performance: <String, PerformanceMeasurement>{
           'hello': PerformanceMeasurement(
             target: 'hello',
             analyticsName: 'bar',
@@ -113,9 +121,9 @@ void main() {
             skipped: false,
             succeeded: true,
           ),
-        });
+        }),
-      });
+      ),
-    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
+    ));
 
     await commandRunner.run(<String>[
       'assemble',
@@ -131,34 +139,45 @@ void main() {
         containsPair('name', 'bar'),
       )),
     );
+  }, overrides: <Type, Generator>{
+    Cache: () => FakeCache(),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
-  testbed.test('flutter assemble does not inject engine revision with local-engine', () async {
+  testUsingContext('flutter assemble does not inject engine revision with local-engine', () async {
-    Environment environment;
+    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand(
-    when(globals.buildSystem.build(any, any, buildSystemConfig: anyNamed('buildSystemConfig')))
+      buildSystem: TestBuildSystem.all(BuildResult(success: true), (Target target, Environment environment) {
-      .thenAnswer((Invocation invocation) async {
+        expect(environment.engineVersion, isNull);
-        environment = invocation.positionalArguments[1] as Environment;
+      })
-        return BuildResult(success: true);
+    ));
-      });
-    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
     await commandRunner.run(<String>['assemble', '-o Output', 'debug_macos_bundle_flutter_assets']);
-
-    expect(environment.engineVersion, isNull);
   }, overrides: <Type, Generator>{
     Artifacts: () => Artifacts.test(localEngine: 'out/host_release'),
+    Cache: () => FakeCache(),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
-  testbed.test('flutter assemble only writes input and output files when the values change', () async {
+  testUsingContext('flutter assemble only writes input and output files when the values change', () async {
-    when(globals.buildSystem.build(any, any, buildSystemConfig: anyNamed('buildSystemConfig')))
+    final BuildSystem buildSystem = TestBuildSystem.list(<BuildResult>[
-      .thenAnswer((Invocation invocation) async {
+      BuildResult(
-        return BuildResult(
+        success: true,
-          success: true,
+        inputFiles: <File>[globals.fs.file('foo')..createSync()],
-          inputFiles: <File>[globals.fs.file('foo')..createSync()],
+        outputFiles: <File>[globals.fs.file('bar')..createSync()],
-          outputFiles: <File>[globals.fs.file('bar')..createSync()],
+      ),
-        );
+      BuildResult(
-      });
+        success: true,
-
+        inputFiles: <File>[globals.fs.file('foo')..createSync()],
-    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand());
+        outputFiles: <File>[globals.fs.file('bar')..createSync()],
+      ),
+      BuildResult(
+        success: true,
+        inputFiles: <File>[globals.fs.file('foo'), globals.fs.file('fizz')..createSync()],
+        outputFiles: <File>[globals.fs.file('bar'), globals.fs.file(globals.fs.path.join('.dart_tool', 'fizz2'))..createSync(recursive: true)],
+      ),
+    ]);
+    final CommandRunner<void> commandRunner = createTestCommandRunner(AssembleCommand(buildSystem: buildSystem));
     await commandRunner.run(<String>[
       'assemble',
       '-o Output',
@@ -186,13 +205,6 @@ void main() {
     expect(inputs.lastModifiedSync(), theDistantPast);
     expect(outputs.lastModifiedSync(), theDistantPast);
 
-    when(globals.buildSystem.build(any, any, buildSystemConfig: anyNamed('buildSystemConfig')))
-      .thenAnswer((Invocation invocation) async {
-        return BuildResult(
-          success: true,
-          inputFiles: <File>[globals.fs.file('foo'), globals.fs.file('fizz')..createSync()],
-          outputFiles: <File>[globals.fs.file('bar'), globals.fs.file(globals.fs.path.join('.dart_tool', 'fizz2'))..createSync(recursive: true)]);
-      });
     await commandRunner.run(<String>[
       'assemble',
       '-o Output',
@@ -204,6 +216,10 @@ void main() {
     expect(inputs.readAsStringSync(), contains('foo'));
     expect(inputs.readAsStringSync(), contains('fizz'));
     expect(inputs.lastModifiedSync(), isNot(theDistantPast));
+  }, overrides: <Type, Generator>{
+    Cache: () => FakeCache(),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
   testWithoutContext('writePerformanceData outputs performance data in JSON form', () {
@@ -236,5 +252,3 @@ void main() {
     });
   });
 }
-
-class MockBuildSystem extends Mock implements BuildSystem {}

packages/flutter_tools/test/commands.shard/hermetic/build_ios_framework_test.dart

@@ -16,6 +16,7 @@ import 'package:mockito/mockito.dart';
 
 import '../../src/common.dart';
 import '../../src/context.dart';
+import '../../src/fakes.dart';
 
 void main() {
   group('build ios-framework', () {
@@ -70,7 +71,7 @@ void main() {
         when(mockFlutterVersion.frameworkVersion).thenReturn(frameworkVersion);
 
         final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
-          buildSystem: MockBuildSystem(),
+          buildSystem: TestBuildSystem.all(BuildResult(success: true)),
           platform: fakePlatform,
           flutterVersion: mockFlutterVersion,
           cache: cache,
@@ -95,7 +96,7 @@ void main() {
         when(mockGitTagVersion.commits).thenReturn(2);
 
         final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
-          buildSystem: MockBuildSystem(),
+          buildSystem: TestBuildSystem.all(BuildResult(success: true)),
           platform: fakePlatform,
           flutterVersion: mockFlutterVersion,
           cache: cache,
@@ -117,7 +118,7 @@ void main() {
         when(mockGitTagVersion.commits).thenReturn(0);
 
         final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
-          buildSystem: MockBuildSystem(),
+          buildSystem: TestBuildSystem.all(BuildResult(success: true)),
           platform: fakePlatform,
           flutterVersion: mockFlutterVersion,
           cache: cache,
@@ -155,7 +156,7 @@ void main() {
 
           testUsingContext('created when forced', () async {
             final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
-              buildSystem: MockBuildSystem(),
+              buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: mockFlutterVersion,
               cache: cache,
@@ -178,7 +179,7 @@ void main() {
 
           testUsingContext('contains license and version', () async {
             final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
-              buildSystem: MockBuildSystem(),
+              buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: mockFlutterVersion,
               cache: cache,
@@ -198,7 +199,7 @@ void main() {
 
           testUsingContext('debug URL', () async {
             final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
-              buildSystem: MockBuildSystem(),
+              buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: mockFlutterVersion,
               cache: cache,
@@ -216,7 +217,7 @@ void main() {
 
           testUsingContext('profile URL', () async {
             final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
-              buildSystem: MockBuildSystem(),
+              buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: mockFlutterVersion,
               cache: cache,
@@ -234,7 +235,7 @@ void main() {
 
           testUsingContext('release URL', () async {
             final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
-              buildSystem: MockBuildSystem(),
+              buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: mockFlutterVersion,
               cache: cache,
@@ -257,4 +258,3 @@ void main() {
 
 class MockFlutterVersion extends Mock implements FlutterVersion {}
 class MockGitTagVersion extends Mock implements GitTagVersion {}
-class MockBuildSystem extends Mock implements BuildSystem {}

packages/flutter_tools/test/commands.shard/hermetic/build_web_test.dart

@@ -16,10 +16,8 @@ import 'package:flutter_tools/src/commands/build_web.dart';
 import 'package:flutter_tools/src/runner/flutter_command.dart';
 import 'package:flutter_tools/src/dart/pub.dart';
 import 'package:flutter_tools/src/features.dart';
-import 'package:flutter_tools/src/globals.dart' as globals;
 import 'package:flutter_tools/src/project.dart';
 import 'package:flutter_tools/src/web/compile.dart';
-import 'package:mockito/mockito.dart';
 
 import '../../src/common.dart';
 import '../../src/context.dart';
@@ -112,7 +110,7 @@ void main() {
     FeatureFlags: () => TestFeatureFlags(isWebEnabled: true),
     Pub: () => FakePub(),
     ProcessManager: () => FakeProcessManager.any(),
-    BuildSystem: () => MockBuildSystem(),
+    BuildSystem: () => TestBuildSystem.all(BuildResult(success: true)),
   });
 
   testUsingContext('hidden if feature flag is not enabled', () async {
@@ -149,7 +147,7 @@ void main() {
     FeatureFlags: () => TestFeatureFlags(isWebEnabled: true),
     Pub: () => FakePub(),
     ProcessManager: () => FakeProcessManager.any(),
-    BuildSystem: () => MockBuildSystem(),
+    BuildSystem: () => TestBuildSystem.all(BuildResult(success: true)),
   });
 }
 
@@ -201,16 +199,8 @@ class UrlLauncherPlugin {}
 ''');
   fileSystem.file(fileSystem.path.join('lib', 'main.dart'))
       .writeAsStringSync('void main() { }');
-
-  // Process calls. We're not testing that these invocations are correct because
-  // that is covered in targets/web_test.dart.
-  when(globals.buildSystem.build(any, any)).thenAnswer((Invocation invocation) async {
-    return BuildResult(success: true);
-  });
 }
 
-class MockBuildSystem extends Mock implements BuildSystem {}
-
 class TestWebBuildCommand extends FlutterCommand {
   TestWebBuildCommand({ bool verboseHelp = false }) :
     webCommand = BuildWebCommand(verboseHelp: verboseHelp) {

packages/flutter_tools/test/commands.shard/permeable/build_bundle_test.dart

@@ -21,6 +21,7 @@ import 'package:flutter_tools/src/globals.dart' as globals;
 
 import '../../src/common.dart';
 import '../../src/context.dart';
+import '../../src/fakes.dart';
 import '../../src/testbed.dart';
 
 void main() {
@@ -210,18 +211,6 @@ void main() {
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
     final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
-    when(globals.buildSystem.build(any, any)).thenAnswer((Invocation invocation) async {
-      final Environment environment = invocation.positionalArguments[1] as Environment;
-      expect(environment.defines, <String, String>{
-        kTargetFile: globals.fs.path.join('lib', 'main.dart'),
-        kBuildMode: 'debug',
-        kTargetPlatform: 'android-arm',
-        kTrackWidgetCreation: 'true',
-        kIconTreeShakerFlag: null,
-      });
-
-      return BuildResult(success: true);
-    });
 
     await runner.run(<String>[
       'bundle',
@@ -231,11 +220,18 @@ void main() {
       '--track-widget-creation'
     ]);
   }, overrides: <Type, Generator>{
-    BuildSystem: () => MockBuildSystem(),
+    BuildSystem: () => TestBuildSystem.all(BuildResult(success: true), (Target target, Environment environment) {
+      expect(environment.defines, <String, String>{
+        kTargetFile: globals.fs.path.join('lib', 'main.dart'),
+        kBuildMode: 'debug',
+        kTargetPlatform: 'android-arm',
+        kTrackWidgetCreation: 'true',
+        kIconTreeShakerFlag: null,
+      });
+    }),
     FileSystem: () => MemoryFileSystem.test(),
     ProcessManager: () => FakeProcessManager.any(),
   });
 }
 
 class MockBundleBuilder extends Mock implements BundleBuilder {}
-class MockBuildSystem extends Mock implements BuildSystem {}

packages/flutter_tools/test/general.shard/bundle_shim_test.dart

@@ -4,35 +4,21 @@
 
 // @dart = 2.8
 
+import 'package:file/memory.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/bundle.dart';
 import 'package:flutter_tools/src/project.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
-import 'package:mockito/mockito.dart';
 
 import '../src/common.dart';
-import '../src/testbed.dart';
+import '../src/context.dart';
+import '../src/fakes.dart';
 
 // Tests for the temporary flutter assemble/bundle shim.
 void main() {
-  Testbed testbed;
+  testUsingContext('Copies assets to expected directory after building', () async {
-
-  setUp(() {
-    testbed = Testbed(overrides: <Type, Generator>{
-      BuildSystem: () => MockBuildSystem(),
-    });
-  });
-
-  test('Copies assets to expected directory after building', () => testbed.run(() async {
-    when(globals.buildSystem.build(any, any)).thenAnswer((Invocation invocation) async {
-      final Environment environment = invocation.positionalArguments[1] as Environment;
-      environment.outputDir.childFile('kernel_blob.bin').createSync(recursive: true);
-      environment.outputDir.childFile('isolate_snapshot_data').createSync();
-      environment.outputDir.childFile('vm_snapshot_data').createSync();
-      environment.outputDir.childFile('LICENSE').createSync(recursive: true);
-      return BuildResult(success: true);
-    });
     await buildWithAssemble(
       buildMode: BuildMode.debug,
       flutterProject: FlutterProject.fromDirectoryTest(globals.fs.currentDirectory),
@@ -45,16 +31,18 @@ void main() {
     expect(globals.fs.file(globals.fs.path.join('example', 'kernel_blob.bin')).existsSync(), true);
     expect(globals.fs.file(globals.fs.path.join('example', 'LICENSE')).existsSync(), true);
     expect(globals.fs.file(globals.fs.path.join('example.d')).existsSync(), false);
-  }));
+  }, overrides: <Type, Generator>{
-
+    FileSystem: () => MemoryFileSystem.test(),
-  test('Handles build system failure', () => testbed.run(() {
+    ProcessManager: () => FakeProcessManager.any(),
-    when(globals.buildSystem.build(any, any)).thenAnswer((Invocation _) async {
+    BuildSystem: () => TestBuildSystem.all(BuildResult(success: true), (Target target, Environment environment) {
-      return BuildResult(
+      environment.outputDir.childFile('kernel_blob.bin').createSync(recursive: true);
-        success: false,
+      environment.outputDir.childFile('isolate_snapshot_data').createSync();
-        exceptions: <String, ExceptionMeasurement>{},
+      environment.outputDir.childFile('vm_snapshot_data').createSync();
-      );
+      environment.outputDir.childFile('LICENSE').createSync(recursive: true);
-    });
+    }),
+  });
 
+  testUsingContext('Handles build system failure', () {
     expect(() => buildWithAssemble(
       buildMode: BuildMode.debug,
       flutterProject: FlutterProject.fromDirectoryTest(globals.fs.currentDirectory),
@@ -64,7 +52,9 @@ void main() {
       depfilePath: 'example.d',
       treeShakeIcons: false,
     ), throwsToolExit());
-  }));
+  }, overrides: <Type, Generator>{
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
+    BuildSystem: () => TestBuildSystem.all(BuildResult(success: false)),
+  });
 }
-
-class MockBuildSystem extends Mock implements BuildSystem {}

packages/flutter_tools/test/general.shard/ios/simulators_test.dart

@@ -11,7 +11,6 @@ import 'package:flutter_tools/src/base/io.dart';
 import 'package:flutter_tools/src/base/logger.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/devfs.dart';
 import 'package:flutter_tools/src/device.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
@@ -986,5 +985,3 @@ flutter:
     });
   });
 }
-
-class MockBuildSystem extends Mock implements BuildSystem {}

packages/flutter_tools/test/general.shard/resident_web_runner_cold_test.dart

@@ -6,15 +6,14 @@
 
 import 'dart:async';
 
+import 'package:file/memory.dart';
 import 'package:flutter_tools/src/base/common.dart';
+import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/logger.dart';
-import 'package:flutter_tools/src/base/platform.dart';
-import 'package:flutter_tools/src/base/terminal.dart';
 import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/isolated/devfs_web.dart';
 import 'package:flutter_tools/src/isolated/resident_web_runner.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
-import 'package:flutter_tools/src/dart/pub.dart';
 import 'package:flutter_tools/src/device.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
 import 'package:flutter_tools/src/project.dart';
@@ -25,42 +24,22 @@ import 'package:mockito/mockito.dart';
 import 'package:webkit_inspection_protocol/webkit_inspection_protocol.dart';
 
 import '../src/common.dart';
+import '../src/context.dart';
 import '../src/fakes.dart';
 import '../src/testbed.dart';
 
 void main() {
-  Testbed testbed;
   ResidentWebRunner residentWebRunner;
   MockFlutterDevice mockFlutterDevice;
   MockWebDevFS mockWebDevFS;
-  MockBuildSystem mockBuildSystem;
 
   setUp(() {
     mockWebDevFS = MockWebDevFS();
-    mockBuildSystem = MockBuildSystem();
     final MockWebDevice mockWebDevice = MockWebDevice();
     mockFlutterDevice = MockFlutterDevice();
     when(mockFlutterDevice.device).thenReturn(mockWebDevice);
     when(mockFlutterDevice.devFS).thenReturn(mockWebDevFS);
     when(mockWebDevFS.sources).thenReturn(<Uri>[]);
-    when(mockBuildSystem.build(any, any)).thenAnswer((Invocation invocation) async {
-      return BuildResult(success: true);
-    });
-    testbed = Testbed(
-      setup: () {
-        final FlutterProject project = FlutterProject.fromDirectoryTest(globals.fs.currentDirectory);
-        residentWebRunner = residentWebRunner = DwdsWebRunnerFactory().createWebRunner(
-          mockFlutterDevice,
-          flutterProject: project,
-          debuggingOptions: DebuggingOptions.disabled(BuildInfo.release),
-          ipv6: true,
-          stayResident: true,
-          urlTunneller: null,
-        ) as ResidentWebRunner;
-      }, overrides: <Type, Generator>{
-        Pub: () => FakePub(),
-      }
-    );
   });
 
   void _setupMocks() {
@@ -68,9 +47,18 @@ void main() {
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file(globals.fs.path.join('web', 'index.html')).createSync(recursive: true);
+    final FlutterProject project = FlutterProject.fromDirectoryTest(globals.fs.currentDirectory);
+    residentWebRunner = DwdsWebRunnerFactory().createWebRunner(
+      mockFlutterDevice,
+      flutterProject: project,
+      debuggingOptions: DebuggingOptions.disabled(BuildInfo.release),
+      ipv6: true,
+      stayResident: true,
+      urlTunneller: null,
+    ) as ResidentWebRunner;
   }
 
-  test('Can successfully run and connect without vmservice', () => testbed.run(() async {
+  testUsingContext('Can successfully run and connect without vmservice', () async {
     _setupMocks();
     final FakeStatusLogger fakeStatusLogger = globals.logger as FakeStatusLogger;
     final MockStatus mockStatus = MockStatus();
@@ -84,43 +72,37 @@ void main() {
     expect(debugConnectionInfo.wsUri, null);
     verify(mockStatus.stop()).called(1);
   }, overrides: <Type, Generator>{
-    BuildSystem: () => mockBuildSystem,
+    BuildSystem: () => TestBuildSystem.all(BuildResult(success: true)),
-    Logger: () => FakeStatusLogger(BufferLogger(
+    Logger: () => FakeStatusLogger(BufferLogger.test()),
-      terminal: AnsiTerminal(
+    FileSystem: () => MemoryFileSystem.test(),
-        stdio: null,
+    ProcessManager: () => FakeProcessManager.any(),
-        platform: const LocalPlatform(),
+  });
-      ),
-      outputPreferences: OutputPreferences.test(),
-    )),
-  }));
 
   // Regression test for https://github.com/flutter/flutter/issues/60613
-  test('ResidentWebRunner calls appFailedToStart if initial compilation fails', () => testbed.run(() async {
+  testUsingContext('ResidentWebRunner calls appFailedToStart if initial compilation fails', () async {
     _setupMocks();
-    when(mockBuildSystem.build(any, any)).thenAnswer((Invocation invocation) async {
+
-      return BuildResult(success: false);
-    });
     expect(() async => await residentWebRunner.run(), throwsToolExit());
     expect(await residentWebRunner.waitForAppToFinish(), 1);
-
   }, overrides: <Type, Generator>{
-    BuildSystem: () => mockBuildSystem,
+    BuildSystem: () => TestBuildSystem.all(BuildResult(success: false)),
-  }));
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
+  });
 
   // Regression test for https://github.com/flutter/flutter/issues/60613
-  test('ResidentWebRunner calls appFailedToStart if error is thrown during startup', () => testbed.run(() async {
+  testUsingContext('ResidentWebRunner calls appFailedToStart if error is thrown during startup', () async {
     _setupMocks();
-    when(mockBuildSystem.build(any, any)).thenAnswer((Invocation invocation) async {
+
-      throw Exception('foo');
-    });
     expect(() async => await residentWebRunner.run(), throwsA(isA<Exception>()));
     expect(await residentWebRunner.waitForAppToFinish(), 1);
-
   }, overrides: <Type, Generator>{
-    BuildSystem: () => mockBuildSystem,
+    BuildSystem: () => TestBuildSystem.error(Exception('foo')),
-  }));
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
+  });
 
-  test('Can full restart after attaching', () => testbed.run(() async {
+  testUsingContext('Can full restart after attaching', () async {
     _setupMocks();
     final Completer<DebugConnectionInfo> connectionInfoCompleter = Completer<DebugConnectionInfo>();
     unawaited(residentWebRunner.run(
@@ -131,28 +113,32 @@ void main() {
 
     expect(result.code, 0);
   }, overrides: <Type, Generator>{
-    BuildSystem: () => mockBuildSystem,
+    BuildSystem: () => TestBuildSystem.all(BuildResult(success: true)),
-  }));
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
+  });
 
-  test('Fails on compilation errors in hot restart', () => testbed.run(() async {
+  testUsingContext('Fails on compilation errors in hot restart', () async {
     _setupMocks();
     final Completer<DebugConnectionInfo> connectionInfoCompleter = Completer<DebugConnectionInfo>();
     unawaited(residentWebRunner.run(
       connectionInfoCompleter: connectionInfoCompleter,
     ));
     await connectionInfoCompleter.future;
-    when(mockBuildSystem.build(any, any)).thenAnswer((Invocation invocation) async {
-      return BuildResult(success: false);
-    });
     final OperationResult result = await residentWebRunner.restart(fullRestart: true);
 
     expect(result.code, 1);
     expect(result.message, contains('Failed to recompile application.'));
   }, overrides: <Type, Generator>{
-    BuildSystem: () => mockBuildSystem,
+    BuildSystem: () => TestBuildSystem.list(<BuildResult>[
-  }));
+      BuildResult(success: true),
+      BuildResult(success: false),
+    ]),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
+  });
 
-  test('Correctly performs a full refresh on attached chrome device.', () => testbed.run(() async {
+  testUsingContext('Correctly performs a full refresh on attached chrome device.', () async {
     _setupMocks();
     final MockChromeDevice chromeDevice = MockChromeDevice();
     final MockChrome chrome = MockChrome();
@@ -184,9 +170,10 @@ void main() {
       'ignoreCache': true,
     })).called(1);
   }, overrides: <Type, Generator>{
-    BuildSystem: () => mockBuildSystem,
+    BuildSystem: () => TestBuildSystem.all(BuildResult(success: true)),
-  }));
+    FileSystem: () => MemoryFileSystem.test(),
-
+    ProcessManager: () => FakeProcessManager.any(),
+  });
 }
 
 class MockWebDevFS extends Mock implements WebDevFS {}
@@ -198,5 +185,4 @@ class MockChrome extends Mock implements Chromium {}
 class MockChromeConnection extends Mock implements ChromeConnection {}
 class MockChromeTab extends Mock implements ChromeTab {}
 class MockWipConnection extends Mock implements WipConnection {}
-class MockBuildSystem extends Mock implements BuildSystem {}
 class MockChromiumLauncher extends Mock implements ChromiumLauncher {}

packages/flutter_tools/test/general.shard/tester/flutter_tester_test.dart

@@ -21,6 +21,7 @@ import 'package:mockito/mockito.dart';
 
 import '../../src/common.dart';
 import '../../src/context.dart';
+import '../../src/fakes.dart';
 
 void main() {
   MemoryFileSystem fileSystem;
@@ -80,26 +81,19 @@ void main() {
     String mainPath;
 
     FakeProcessManager fakeProcessManager;
-    MockBuildSystem mockBuildSystem;
+    TestBuildSystem buildSystem;
 
     final Map<Type, Generator> startOverrides = <Type, Generator>{
       Platform: () => FakePlatform(operatingSystem: 'linux'),
       FileSystem: () => fileSystem,
       ProcessManager: () => fakeProcessManager,
       Artifacts: () => Artifacts.test(),
-      BuildSystem: () => mockBuildSystem,
+      BuildSystem: () => buildSystem,
     };
 
     setUp(() {
-      mockBuildSystem = MockBuildSystem();
+      buildSystem = TestBuildSystem.all(BuildResult(success: true));
       fakeProcessManager = FakeProcessManager.list(<FakeCommand>[]);
-
-      when(mockBuildSystem.build(
-        any,
-        any,
-      )).thenAnswer((_) async {
-        return BuildResult(success: true);
-      });
       device = FlutterTesterDevice('flutter-tester',
         fileSystem: fileSystem,
         processManager: fakeProcessManager,
@@ -194,5 +188,4 @@ FlutterTesterDevices setUpFlutterTesterDevices() {
   );
 }
 
-class MockBuildSystem extends Mock implements BuildSystem {}
 class MockFlutterVersion extends Mock implements FlutterVersion {}

packages/flutter_tools/test/src/fakes.dart

@@ -12,6 +12,7 @@ import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/io.dart';
 import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/os.dart';
+import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/convert.dart';
 import 'package:flutter_tools/src/dart/pub.dart';
@@ -443,3 +444,63 @@ class FakePub extends Fake implements Pub {
     bool checkUpToDate = false,
   }) async { }
 }
+
+class TestBuildSystem implements BuildSystem {
+  /// Create a [BuildSystem] instance that returns the provided results in order.
+  TestBuildSystem.list(this._results, [this._onRun])
+    : _exception = null,
+      _singleResult = null;
+
+  /// Create a [BuildSystem] instance that returns the provided result for every build
+  /// and buildIncremental request.
+  TestBuildSystem.all(this._singleResult, [this._onRun])
+    : _exception = null,
+      _results = <BuildResult>[];
+
+  /// Create a [BuildSystem] instance that always throws the provided error for every build
+  /// and buildIncremental request.
+  TestBuildSystem.error(this._exception)
+    : _singleResult = null,
+      _results = <BuildResult>[],
+      _onRun = null;
+
+  final List<BuildResult> _results;
+  final BuildResult _singleResult;
+  final dynamic _exception;
+  final void Function(Target target, Environment environment) _onRun;
+  int _nextResult = 0;
+
+  @override
+  Future<BuildResult> build(Target target, Environment environment, {BuildSystemConfig buildSystemConfig = const BuildSystemConfig()}) async {
+    if (_onRun != null) {
+      _onRun(target, environment);
+    }
+    if (_exception != null) {
+      throw _exception;
+    }
+    if (_singleResult != null) {
+      return _singleResult;
+    }
+    if (_nextResult >= _results.length) {
+      throw StateError('Unexpected buildIncremental request of ${target.name}');
+    }
+    return _results[_nextResult++];
+  }
+
+  @override
+  Future<BuildResult> buildIncremental(Target target, Environment environment, BuildResult previousBuild) async {
+    if (_onRun != null) {
+      _onRun(target, environment);
+    }
+    if (_exception != null) {
+      throw _exception;
+    }
+    if (_singleResult != null) {
+      return _singleResult;
+    }
+    if (_nextResult >= _results.length) {
+      throw StateError('Unexpected buildIncremental request of ${target.name}');
+    }
+    return _results[_nextResult++];
+  }
+}