Extra defensive programming for pub modification time assert (#42491)

packages/flutter_tools/lib/src/dart/pub.dart

@@ -158,6 +158,8 @@ class _DefaultPub implements Pub {
       return;
     }
 
+    final DateTime originalPubspecYamlModificationTime = pubSpecYaml.lastModifiedSync();
+
     if (!checkLastModified || _shouldRunPubGet(pubSpecYaml: pubSpecYaml, dotPackages: dotPackages)) {
       final String command = upgrade ? 'upgrade' : 'get';
       final Status status = logger.startProgress(
@@ -189,11 +191,34 @@ class _DefaultPub implements Pub {
     if (!dotPackages.existsSync()) {
       throwToolExit('$directory: pub did not create .packages file.');
     }
-
-    if (dotPackages.lastModifiedSync().isBefore(pubSpecYaml.lastModifiedSync())) {
-      throwToolExit('$directory: pub did not update .packages file '
-          '(pubspec.yaml timestamp: ${pubSpecYaml.lastModifiedSync()}; '
-          '.packages timestamp: ${dotPackages.lastModifiedSync()}).');
+    if (pubSpecYaml.lastModifiedSync() != originalPubspecYamlModificationTime) {
+      throwToolExit('$directory: unexpected concurrent modification of pubspec.yaml while running pub.');
+    }
+    // We don't check if dotPackages was actually modified, because as far as we can tell sometimes
+    // pub will decide it does not need to actually modify it.
+    // Since we rely on the file having a more recent timestamp, though, we do manually force the
+    // file to be more recently modified.
+    final DateTime now = DateTime.now();
+    if (now.isBefore(originalPubspecYamlModificationTime)) {
+      printError(
+        'Warning: File "${fs.path.absolute(pubSpecYaml.path)}" was created in the future. '
+        'Optimizations that rely on comparing time stamps will be unreliable. Check your '
+        'system clock for accuracy.\n'
+        'The timestamp was: $originalPubspecYamlModificationTime\n'
+        'The time now is: $now'
+      );
+    } else {
+      dotPackages.setLastModifiedSync(now);
+      final DateTime newDotPackagesTimestamp = dotPackages.lastModifiedSync();
+      if (newDotPackagesTimestamp.isBefore(originalPubspecYamlModificationTime)) {
+        printError(
+          'Warning: Failed to set timestamp of "${fs.path.absolute(dotPackages.path)}". '
+          'Tried to set timestamp to $now, but new timestamp is $newDotPackagesTimestamp.'
+        );
+        if (newDotPackagesTimestamp.isAfter(now)) {
+          printError('Maybe the file was concurrently modified?');
+        }
+      }
     }
   }
 

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

@@ -48,7 +48,7 @@ void main() {
       inRepo(<String>[]);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 }

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

@@ -100,7 +100,7 @@ void main() {
         await loggerSubscription.cancel();
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Logger: () => logger,
       });
 
@@ -118,7 +118,7 @@ void main() {
                throwsA(isA<ToolExit>()));
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Logger: () => logger,
       });
 
@@ -198,7 +198,7 @@ void main() {
         expect(flutterDevice.fileSystemRoots, const <String>[filesystemRoot]);
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
       });
 
       testUsingContext('exits when ipv6 is specified and debug-port is not', () async {
@@ -222,7 +222,7 @@ void main() {
         );
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
       },);
 
       testUsingContext('exits when observatory-port is specified and debug-port is not', () async {
@@ -246,7 +246,7 @@ void main() {
         );
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
       },);
     });
 
@@ -308,7 +308,7 @@ void main() {
       )).called(1);
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     group('forwarding to given port', () {
@@ -351,7 +351,7 @@ void main() {
         await loggerSubscription.cancel();
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Logger: () => logger,
       });
 
@@ -375,7 +375,7 @@ void main() {
         await loggerSubscription.cancel();
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Logger: () => logger,
       });
 
@@ -406,7 +406,7 @@ void main() {
         await loggerSubscription.cancel();
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Logger: () => logger,
       });
 
@@ -438,7 +438,7 @@ void main() {
         await loggerSubscription.cancel();
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Logger: () => logger,
       });
     });
@@ -452,7 +452,7 @@ void main() {
       expect(testLogger.statusText, contains('No supported devices connected'));
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('exits when multiple devices connected', () async {
@@ -477,7 +477,7 @@ void main() {
       expect(testLogger.statusText, contains('yy2'));
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 }

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

@@ -57,7 +57,7 @@ void main() {
     }, overrides: <Type, Generator>{
       Platform: () => linuxPlatform,
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FuchsiaArtifacts: () => fuchsiaArtifacts,
     });
 
@@ -75,7 +75,7 @@ void main() {
     }, overrides: <Type, Generator>{
       Platform: () => linuxPlatform,
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FuchsiaArtifacts: () => fuchsiaArtifacts,
     });
 
@@ -98,7 +98,7 @@ void main() {
     }, overrides: <Type, Generator>{
       Platform: () => windowsPlatform,
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FuchsiaArtifacts: () => fuchsiaArtifacts,
     });
 
@@ -121,7 +121,7 @@ void main() {
     }, overrides: <Type, Generator>{
       Platform: () => linuxPlatform,
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FuchsiaArtifacts: () => fuchsiaArtifactsNoCompiler,
     });
   });
@@ -147,7 +147,7 @@ void main() {
   }, overrides: <Type, Generator>{
     Platform: () => linuxPlatform,
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     FuchsiaSdk: () => fuchsiaSdk,
   });
 }

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

@@ -83,7 +83,7 @@ void main() {
   }, overrides: <Type, Generator>{
     Platform: () => linuxPlatform,
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     FeatureFlags: () => TestFeatureFlags(isLinuxEnabled: true),
   });
 
@@ -98,7 +98,7 @@ void main() {
   }, overrides: <Type, Generator>{
     Platform: () => notLinuxPlatform,
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     FeatureFlags: () => TestFeatureFlags(isLinuxEnabled: true),
   });
 
@@ -187,7 +187,7 @@ BINARY_NAME=fizz_bar
     expect(makefileExecutableName(flutterProject.linux), 'fizz_bar');
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     FeatureFlags: () => TestFeatureFlags(isLinuxEnabled: true),
   });
 

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

@@ -120,7 +120,7 @@ void main() {
   }, overrides: <Type, Generator>{
     Platform: () => notMacosPlatform,
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     FeatureFlags: () => TestFeatureFlags(isMacOSEnabled: true),
   });
 

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

@@ -67,7 +67,7 @@ void main() {
   }, overrides: <Type, Generator>{
     Platform: () => windowsPlatform,
     FileSystem: () => MemoryFileSystem(style: FileSystemStyle.windows),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     VisualStudio: () => mockVisualStudio,
     FeatureFlags: () => TestFeatureFlags(isWindowsEnabled: true),
   });
@@ -82,7 +82,7 @@ void main() {
   }, overrides: <Type, Generator>{
     Platform: () => windowsPlatform,
     FileSystem: () => MemoryFileSystem(style: FileSystemStyle.windows),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     VisualStudio: () => mockVisualStudio,
     FeatureFlags: () => TestFeatureFlags(isWindowsEnabled: true),
   });
@@ -102,7 +102,7 @@ void main() {
   }, overrides: <Type, Generator>{
     Platform: () => notWindowsPlatform,
     FileSystem: () => MemoryFileSystem(style: FileSystemStyle.windows),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     VisualStudio: () => mockVisualStudio,
     FeatureFlags: () => TestFeatureFlags(isWindowsEnabled: true),
   });

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

@@ -53,7 +53,7 @@ void main() {
       verify(xcodeProjectInterpreter.cleanWorkspace(any, 'Runner')).called(2);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       Xcode: () => mockXcode,
       XcodeProjectInterpreter: () => mockXcodeProjectInterpreter,
     });

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

@@ -84,7 +84,7 @@ void main() {
       }
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('returns 1 when app fails to run', () async {
@@ -112,7 +112,7 @@ void main() {
       }
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('returns 1 when app file is outside package', () async {
@@ -135,7 +135,7 @@ void main() {
       }
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('returns 1 when app file is in the root dir', () async {
@@ -159,7 +159,7 @@ void main() {
       }
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('returns 0 when test ends successfully', () async {
@@ -192,7 +192,7 @@ void main() {
       expect(testLogger.errorText, isEmpty);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('returns exitCode set by test runner', () async {
@@ -229,7 +229,7 @@ void main() {
       }
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     group('findTargetDevice', () {
@@ -244,7 +244,7 @@ void main() {
         expect(device.name, 'specified-device');
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
       });
     });
 
@@ -255,7 +255,7 @@ void main() {
         expect(await findTargetDevice(), isNull);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: platform,
       });
 
@@ -268,7 +268,7 @@ void main() {
         expect(device.name, 'mock-android-device');
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: platform,
       });
 
@@ -300,7 +300,7 @@ void main() {
         expect(device.name, 'mock-android-device');
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: platform,
       });
     }
@@ -328,7 +328,7 @@ void main() {
         expect(device.name, 'mock-simulator');
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: macOsPlatform,
       });
     });
@@ -400,7 +400,7 @@ void main() {
         ));
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
       });
 
       testUsingContext('does not use pre-built app if --build arg provided', () async {
@@ -428,7 +428,7 @@ void main() {
         ));
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
       });
 
       testUsingContext('uses prebuilt app if --no-build arg provided', () async {
@@ -456,7 +456,7 @@ void main() {
         ));
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
       });
     });
   });

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

@@ -52,7 +52,7 @@ void main() {
       expect(fs.file(outputFile).readAsStringSync(), contains('__flutter_completion'));
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       Stdio: () => mockStdio,
     });
 
@@ -73,7 +73,7 @@ void main() {
       expect(fs.file(outputFile).readAsStringSync(), isEmpty);
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       Stdio: () => mockStdio,
     });
 
@@ -88,7 +88,7 @@ void main() {
       expect(fs.file(outputFile).readAsStringSync(), contains('__flutter_completion'));
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       Stdio: () => mockStdio,
     });
   });

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

@@ -111,7 +111,7 @@ void main() {
     ]), throwsA(isInstanceOf<ToolExit>()));
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     FeatureFlags: () => TestFeatureFlags(isWindowsEnabled: false),
   });
 
@@ -129,7 +129,7 @@ void main() {
     ]), throwsA(isInstanceOf<ToolExit>()));
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     FeatureFlags: () => TestFeatureFlags(isLinuxEnabled: false),
   });
 
@@ -147,7 +147,7 @@ void main() {
     ]), throwsA(isInstanceOf<ToolExit>()));
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     FeatureFlags: () => TestFeatureFlags(isMacOSEnabled: false),
   });
 
@@ -165,7 +165,7 @@ void main() {
     ]);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     FeatureFlags: () => TestFeatureFlags(isWindowsEnabled: true),
   });
 
@@ -183,7 +183,7 @@ void main() {
     ]);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     FeatureFlags: () => TestFeatureFlags(isLinuxEnabled: true),
   });
 
@@ -201,7 +201,7 @@ void main() {
     ]);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     FeatureFlags: () => TestFeatureFlags(isMacOSEnabled: true),
   });
 
@@ -230,9 +230,9 @@ void main() {
       '--track-widget-creation'
     ]);
   }, overrides: <Type, Generator>{
-    FileSystem: () => MemoryFileSystem(),
     BuildSystem: () => MockBuildSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    FileSystem: () => MemoryFileSystem(),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 }
 

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

@@ -108,7 +108,7 @@ void main() {
         'FLUTTER_ANALYTICS_LOG_FILE': 'test',
       }),
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('Usage records multiple features in experiment setting', () async {
@@ -130,7 +130,7 @@ void main() {
         'FLUTTER_ANALYTICS_LOG_FILE': 'test',
       }),
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 
@@ -223,7 +223,7 @@ void main() {
       expect(log.contains(formatDateTime(dateTime)), isTrue);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       SystemClock: () => mockClock,
       Platform: () => FakePlatform(
         environment: <String, String>{
@@ -249,7 +249,7 @@ void main() {
       expect(log.contains(formatDateTime(dateTime)), isTrue);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       SystemClock: () => mockClock,
       Platform: () => FakePlatform(
         environment: <String, String>{

packages/flutter_tools/test/general.shard/android/android_device_test.dart

@@ -398,7 +398,7 @@ flutter:
     expect(AndroidDevice('test').isSupportedForProject(flutterProject), true);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
   testUsingContext('isSupportedForProject is true with editable host app', () async {
@@ -410,7 +410,7 @@ flutter:
     expect(AndroidDevice('test').isSupportedForProject(flutterProject), true);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
   testUsingContext('isSupportedForProject is false with no host app and no module', () async {
@@ -421,7 +421,7 @@ flutter:
     expect(AndroidDevice('test').isSupportedForProject(flutterProject), false);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
   group('emulatorId', () {

packages/flutter_tools/test/general.shard/android/android_sdk_test.dart

@@ -45,7 +45,7 @@ void main() {
       expect(sdk.latestVersion.sdkLevel, 23);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('parse sdk N', () {
@@ -57,7 +57,7 @@ void main() {
       expect(sdk.latestVersion.sdkLevel, 24);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('returns sdkmanager path', () {
@@ -68,7 +68,7 @@ void main() {
       expect(sdk.sdkManagerPath, fs.path.join(sdk.directory, 'tools', 'bin', 'sdkmanager'));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('returns sdkmanager version', () {
@@ -161,7 +161,7 @@ void main() {
           expect(sdk.ndk.compilerArgs, <String>['--sysroot', realNdkSysroot]);
         }, overrides: <Type, Generator>{
           FileSystem: () => fs,
-          ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+          ProcessManager: () => FakeProcessManager.any(),
           Platform: () => FakePlatform(operatingSystem: os),
         });
 
@@ -196,7 +196,7 @@ void main() {
           expect(sdk.ndk.compilerArgs, <String>['--sysroot', realNdkSysroot, '-fuse-ld=$realNdkLinker']);
         }, overrides: <Type, Generator>{
           FileSystem: () => fs,
-          ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+          ProcessManager: () => FakeProcessManager.any(),
           Platform: () => FakePlatform(operatingSystem: os),
         });
       });
@@ -214,7 +214,7 @@ void main() {
           expect(explanation, contains('Can not locate ndk-bundle'));
         }, overrides: <Type, Generator>{
           FileSystem: () => fs,
-          ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+          ProcessManager: () => FakeProcessManager.any(),
           Platform: () => FakePlatform(operatingSystem: os),
         });
       }

packages/flutter_tools/test/general.shard/android/android_studio_test.dart

@@ -66,7 +66,7 @@ void main() {
           equals('/home/me/.AndroidStudioWithCheese5.0/config/plugins'));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       // Custom home paths are not supported on macOS nor Windows yet,
       // so we force the platform to fake Linux here.
       Platform: () => linuxPlatform(),
@@ -86,7 +86,7 @@ void main() {
           equals(fs.path.join(homeMac, 'Library', 'Application Support', 'AndroidStudio3.3')));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       // Custom home paths are not supported on macOS nor Windows yet,
       // so we force the platform to fake Linux here.
       Platform: () => macPlatform(),
@@ -116,7 +116,7 @@ void main() {
           equals(fs.path.join(homeMac, 'Library', 'Application Support', 'AndroidStudio3.3')));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       // Custom home paths are not supported on macOS nor Windows yet,
       // so we force the platform to fake Linux here.
       Platform: () => macPlatform(),

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

@@ -211,7 +211,7 @@ void main() {
   group('PrebuiltIOSApp', () {
     final Map<Type, Generator> overrides = <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       PlistParser: () => MockPlistUtils(),
       Platform: _kNoColorTerminalPlatform,
       OperatingSystemUtils: () => MockOperatingSystemUtils(),
@@ -363,7 +363,7 @@ void main() {
   group('FuchsiaApp', () {
     final Map<Type, Generator> overrides = <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       Platform: _kNoColorTerminalPlatform,
       OperatingSystemUtils: () => MockOperatingSystemUtils(),
     };

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

@@ -45,7 +45,7 @@ void main() {
       }, overrides: <Type, Generator>{
         Cache: () => Cache(rootOverride: tempDir),
         FileSystem: () => memoryFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: () => FakePlatform(operatingSystem: 'linux'),
       });
 
@@ -65,7 +65,7 @@ void main() {
       }, overrides: <Type, Generator>{
         Cache: () => Cache(rootOverride: tempDir),
         FileSystem: () => memoryFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: () => FakePlatform(operatingSystem: 'linux'),
       });
     });
@@ -95,7 +95,7 @@ void main() {
         );
       }, overrides: <Type, Generator>{
         FileSystem: () => memoryFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: () => FakePlatform(operatingSystem: 'linux'),
       });
 
@@ -114,7 +114,7 @@ void main() {
         );
       }, overrides: <Type, Generator>{
         FileSystem: () => memoryFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: () => FakePlatform(operatingSystem: 'linux'),
       });
 
@@ -122,7 +122,7 @@ void main() {
         expect(artifacts.getArtifactPath(Artifact.engineDartBinary), contains('.exe'));
       }, overrides: <Type, Generator>{
         FileSystem: () => memoryFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: () => FakePlatform(operatingSystem: 'windows'),
       });
 
@@ -130,7 +130,7 @@ void main() {
         expect(artifacts.getArtifactPath(Artifact.engineDartBinary), isNot(contains('.exe')));
       }, overrides: <Type, Generator>{
         FileSystem: () => memoryFileSystem,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: () => FakePlatform(operatingSystem: 'linux'),
       });
     });

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

@@ -126,7 +126,7 @@ $fontsSection
       expect(bundle.entries.containsKey('FontManifest.json'), isTrue);
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('App font uses font file from package', () async {
@@ -155,7 +155,7 @@ $fontsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('App font uses local font file and package font file', () async {
@@ -188,7 +188,7 @@ $fontsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('App uses package font with own font file', () async {
@@ -222,7 +222,7 @@ $fontsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('App uses package font with font file from another package', () async {
@@ -257,7 +257,7 @@ $fontsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('App uses package font with properties and own font file', () async {
@@ -293,7 +293,7 @@ $fontsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('App uses local font and package font with own font file.', () async {
@@ -333,7 +333,7 @@ $fontsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 }

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

@@ -135,7 +135,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('No assets are bundled when the package has an asset that is not listed', () async {
@@ -163,7 +163,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('One asset is bundled when the package has and lists one asset its pubspec', () async {
@@ -191,7 +191,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext("One asset is bundled when the package has one asset, listed in the app's pubspec", () async {
@@ -219,7 +219,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('One asset and its variant are bundled when the package has an asset and a variant, and lists the asset in its pubspec', () async {
@@ -247,7 +247,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('One asset and its variant are bundled when the package has an asset and a variant, and the app lists the asset in its pubspec', () async {
@@ -278,7 +278,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('Two assets are bundled when the package has and lists two assets in its pubspec', () async {
@@ -307,7 +307,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext("Two assets are bundled when the package has two assets, listed in the app's pubspec", () async {
@@ -343,7 +343,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('Two assets are bundled when two packages each have and list an asset their pubspec', () async {
@@ -383,7 +383,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext("Two assets are bundled when two packages each have an asset, listed in the app's pubspec", () async {
@@ -426,7 +426,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('One asset is bundled when the app depends on a package, listing in its pubspec an asset from another package', () async {
@@ -461,7 +461,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 
@@ -491,7 +491,7 @@ $assetsSection
     );
   }, overrides: <Type, Generator>{
     FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
   });
 
   group('AssetBundle assets from scanned paths', () {
@@ -523,7 +523,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('Two assets are bundled when listing one and scanning second directory', () async {
@@ -554,7 +554,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('One asset is bundled with variant, scanning wrong directory', () async {
@@ -580,7 +580,7 @@ $assetsSection
       assert(bundle.entries['AssetManifest.json'] == null,'Invalid pubspec.yaml should not generate AssetManifest.json'  );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 
@@ -612,7 +612,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('No asset is bundled with variant, no assets or directories are listed', () async {
@@ -641,7 +641,7 @@ $assetsSection
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('Expect error generating manifest, wrong non-existing directory is listed', () async {
@@ -675,7 +675,7 @@ $assetsSection
       }
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
   });

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

@@ -38,7 +38,7 @@ void main() {
       expect(ab.entries.length, greaterThan(0));
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('empty pubspec', () async {
@@ -56,7 +56,7 @@ void main() {
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('wildcard directories are updated when filesystem changes', () async {
@@ -96,7 +96,7 @@ flutter:
       expect(bundle.entries.length, 5);
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('handle removal of wildcard directories', () async {
@@ -146,7 +146,7 @@ name: example''')
       expect(bundle.entries.length, 4);
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     // https://github.com/flutter/flutter/issues/42723
@@ -175,7 +175,7 @@ flutter:
       expect(bundle.needsBuild(manifestPath: 'pubspec.yaml'), false);
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 

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

@@ -92,7 +92,7 @@ flutter:
       }
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 }

packages/flutter_tools/test/general.shard/base/build_test.dart

@@ -254,7 +254,7 @@ void main() {
       AndroidSdk: () => mockAndroidSdk,
       Artifacts: () => mockArtifacts,
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       GenSnapshot: () => genSnapshot,
       Xcode: () => mockXcode,
       Logger: () => bufferLogger,

packages/flutter_tools/test/general.shard/base/file_system_test.dart

@@ -22,7 +22,7 @@ void main() {
       expect(fs.isDirectorySync('foo/bar'), true);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('throws tool exit on failure to create', () async {
@@ -30,7 +30,7 @@ void main() {
       expect(() => ensureDirectoryExists('foo/bar.flx'), throwsToolExit());
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 
@@ -86,7 +86,7 @@ void main() {
       expect(destination.childDirectory('nested').childFile('a.txt').existsSync(), isFalse);
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 

packages/flutter_tools/test/general.shard/base/fingerprint_test.dart

@@ -30,7 +30,7 @@ void main() {
 
     final Map<Type, Generator> contextOverrides = <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     };
 
     testUsingContext('throws when depfile is malformed', () {
@@ -293,7 +293,7 @@ void main() {
         );
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
       });
 
       testUsingContext('populates checksums for valid files', () {
@@ -307,7 +307,7 @@ void main() {
         expect(jsonObject['files']['b.dart'], '6f144e08b58cd0925328610fad7ac07c');
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
       });
 
       testUsingContext('includes framework version', () {
@@ -489,7 +489,7 @@ void main() {
 
     final Map<Type, Generator> contextOverrides = <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     };
 
     testUsingContext('returns one file if only one is listed', () {

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

@@ -52,7 +52,7 @@ void main() {
       fs.directory('windows').createSync();
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(style: FileSystemStyle.windows),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       Platform: () => platform,
     });
   });

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

@@ -64,7 +64,7 @@ void main() {
       Cache.releaseLockEarly();
     }, overrides: <Type, Generator>{
       FileSystem: () => mockFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('throws tool exit when lockfile open fails', () async {
@@ -73,7 +73,7 @@ void main() {
       expect(() async => await Cache.lock(), throwsA(isA<ToolExit>()));
     }, overrides: <Type, Generator>{
       FileSystem: () => mockFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('should not throw when FLUTTER_ALREADY_LOCKED is set', () async {
@@ -102,7 +102,7 @@ void main() {
     }, overrides: <Type, Generator>{
       Cache: ()=> mockCache,
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('Gradle wrapper should be up to date, only if all cached artifact are available', () {
@@ -118,7 +118,7 @@ void main() {
     }, overrides: <Type, Generator>{
       Cache: ()=> mockCache,
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     test('should not be up to date, if some cached artifact is not', () {
@@ -210,7 +210,7 @@ void main() {
     expect(flattenNameSubdirs(Uri.parse('https://www.flutter.dev')), 'www.flutter.dev');
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
   test('Unstable artifacts', () {
@@ -261,7 +261,7 @@ void main() {
     }, overrides: <Type, Generator>{
       Cache: ()=> mockCache,
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       HttpClientFactory: () => () => fakeHttpClient,
       OperatingSystemUtils: () => mockOperatingSystemUtils,
       Platform: () => fakePlatform,

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

@@ -41,7 +41,7 @@ void main() {
   }, overrides: <Type, Generator>{
     Artifacts: () => LocalEngineArtifacts('/engine', 'ios_profile', 'host_profile'),
     FileSystem: () => memoryFileSystem,
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
   testUsingContext('build aot prints error if Clang version invalid', () async {

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

@@ -7,11 +7,13 @@ import 'dart:collection';
 
 import 'package:file/file.dart';
 import 'package:file/memory.dart';
-import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/base/common.dart';
 import 'package:flutter_tools/src/base/context.dart';
+import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/io.dart';
 import 'package:flutter_tools/src/base/platform.dart';
+import 'package:flutter_tools/src/base/utils.dart';
+import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/dart/pub.dart';
 import 'package:flutter_tools/src/reporting/reporting.dart';
 
@@ -22,6 +24,7 @@ import 'package:quiver/testing/async.dart';
 import '../../src/common.dart';
 import '../../src/context.dart';
 import '../../src/mocks.dart' as mocks;
+import '../../src/testbed.dart';
 
 void main() {
   setUpAll(() {
@@ -239,6 +242,117 @@ void main() {
     Usage: () => MockUsage(),
     Pub: () => const Pub(),
   });
+
+  test('Pub error handling', () {
+    final MemoryFileSystem fileSystem = MemoryFileSystem();
+    final FakeProcessManager processManager = FakeProcessManager.list(<FakeCommand>[
+      FakeCommand(
+        command: const <String>[
+          '/bin/cache/dart-sdk/bin/pub',
+          '--verbosity=warning',
+          'get',
+          '--no-precompile',
+        ],
+        onRun: () {
+          fs.file('.packages')
+            ..setLastModifiedSync(DateTime(2002));
+        }
+      ),
+      const FakeCommand(
+        command: <String>[
+          '/bin/cache/dart-sdk/bin/pub',
+          '--verbosity=warning',
+          'get',
+          '--no-precompile',
+        ],
+      ),
+      FakeCommand(
+        command: const <String>[
+          '/bin/cache/dart-sdk/bin/pub',
+          '--verbosity=warning',
+          'get',
+          '--no-precompile',
+        ],
+        onRun: () {
+          fs.file('pubspec.yaml')
+            ..setLastModifiedSync(DateTime(2002));
+        }
+      ),
+    ]);
+    Testbed().run(() async {
+      // the good scenario: .packages is old, pub updates the file.
+      fs.file('.packages')
+        ..createSync()
+        ..setLastModifiedSync(DateTime(2000));
+      fs.file('pubspec.yaml')
+        ..createSync()
+        ..setLastModifiedSync(DateTime(2001));
+      await pub.get(context: PubContext.flutterTests, checkLastModified: true); // pub sets date of .packages to 2002
+      expect(testLogger.statusText, 'Running "flutter pub get" in /...\n');
+      expect(testLogger.errorText, isEmpty);
+      expect(fs.file('pubspec.yaml').lastModifiedSync(), DateTime(2001)); // because nothing should touch it
+      expect(fs.file('.packages').lastModifiedSync(), isNot(DateTime(2000))); // because pub changes it to 2002
+      expect(fs.file('.packages').lastModifiedSync(), isNot(DateTime(2002))); // because we set the timestamp again after pub
+      testLogger.clear();
+      // bad scenario 1: pub doesn't update file; doesn't matter, because we do instead
+      fs.file('.packages')
+        ..setLastModifiedSync(DateTime(2000));
+      fs.file('pubspec.yaml')
+        ..setLastModifiedSync(DateTime(2001));
+      await pub.get(context: PubContext.flutterTests, checkLastModified: true); // pub does nothing
+      expect(testLogger.statusText, 'Running "flutter pub get" in /...\n');
+      expect(testLogger.errorText, isEmpty);
+      expect(fs.file('pubspec.yaml').lastModifiedSync(), DateTime(2001)); // because nothing should touch it
+      expect(fs.file('.packages').lastModifiedSync(), isNot(DateTime(2000))); // because we set the timestamp
+      expect(fs.file('.packages').lastModifiedSync(), isNot(DateTime(2002))); // just in case FakeProcessManager is buggy
+      testLogger.clear();
+      // bad scenario 2: pub changes pubspec.yaml instead
+      fs.file('.packages')
+        ..setLastModifiedSync(DateTime(2000));
+      fs.file('pubspec.yaml')
+        ..setLastModifiedSync(DateTime(2001));
+      try {
+        await pub.get(context: PubContext.flutterTests, checkLastModified: true);
+        expect(true, isFalse, reason: 'pub.get did not throw');
+      } catch (error) {
+        expect(error.runtimeType, Exception);
+        expect(error.message, '/: unexpected concurrent modification of pubspec.yaml while running pub.');
+      }
+      expect(testLogger.statusText, 'Running "flutter pub get" in /...\n');
+      expect(testLogger.errorText, isEmpty);
+      expect(fs.file('pubspec.yaml').lastModifiedSync(), DateTime(2002)); // because fake pub above touched it
+      expect(fs.file('.packages').lastModifiedSync(), DateTime(2000)); // because nothing touched it
+      // bad scenario 3: pubspec.yaml was created in the future
+      fs.file('.packages')
+        ..setLastModifiedSync(DateTime(2000));
+      fs.file('pubspec.yaml')
+        ..setLastModifiedSync(DateTime(9999));
+      assert(DateTime(9999).isAfter(DateTime.now()));
+      await pub.get(context: PubContext.flutterTests, checkLastModified: true); // pub does nothing
+      expect(testLogger.statusText, 'Running "flutter pub get" in /...\n');
+      expect(testLogger.errorText, startsWith(
+        'Warning: File "/pubspec.yaml" was created in the future. Optimizations that rely on '
+        'comparing time stamps will be unreliable. Check your system clock for accuracy.\n'
+        'The timestamp was: 2000-01-01 00:00:00.000\n'
+      ));
+      testLogger.clear();
+    }, overrides: <Type, Generator>{
+      FileSystem: () => fileSystem,
+      ProcessManager: () => processManager,
+      Pub: () => const Pub(),
+      Platform: () => FakePlatform(
+        operatingSystem: 'linux', // so that the command executed is consistent
+        environment: <String, String>{},
+      ),
+      BotDetector: () => const BotDetectorAlwaysNo(), // so that the test never adds --trace to the pub command
+    });
+  });
+}
+
+class BotDetectorAlwaysNo implements BotDetector {
+  const BotDetectorAlwaysNo();
+  @override
+  bool get isRunningOnBot => false;
 }
 
 typedef StartCallback = void Function(List<dynamic> command);

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

@@ -89,7 +89,7 @@ void main() {
       expect(content.isModified, isFalse);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     }, skip: Platform.isWindows); // TODO(jonahwilliams): fix or disable this functionality.
   });
 
@@ -159,7 +159,7 @@ void main() {
       verify(httpRequest.close()).called(kFailedAttempts + 1);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 
@@ -208,7 +208,7 @@ void main() {
       expect(report.success, true);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('delete dev file system', () async {
@@ -218,7 +218,7 @@ void main() {
       expect(devFS.assetPathsToEvict, isEmpty);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('cleanup preexisting file system', () async {
@@ -246,7 +246,7 @@ void main() {
       expect(devFS.assetPathsToEvict, isEmpty);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('reports unsuccessful compile when errors are returned', () async {
@@ -276,7 +276,7 @@ void main() {
       expect(devFS.lastCompiled, previousCompile);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('correctly updates last compiled time when compilation does not fail', () async {
@@ -310,7 +310,7 @@ void main() {
       expect(devFS.lastCompiled, isNot(previousCompile));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 }

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

@@ -652,7 +652,7 @@ flutter:
         },
         overrides: <Type, Generator>{
           FileSystem: () => filesystem,
-          ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+          ProcessManager: () => FakeProcessManager.any(),
         },
       );
     }

packages/flutter_tools/test/general.shard/fuchsia/fuchsia_device_test.dart

@@ -75,7 +75,7 @@ void main() {
       expect(device.isSupportedForProject(FlutterProject.current()), true);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('supported for project', () async {
@@ -85,7 +85,7 @@ void main() {
       expect(device.isSupportedForProject(FlutterProject.current()), true);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('not supported for project', () async {
@@ -94,7 +94,7 @@ void main() {
       expect(device.isSupportedForProject(FlutterProject.current()), false);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 
@@ -448,7 +448,7 @@ void main() {
       expect(launchResult.hasObservatory, isFalse);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FuchsiaDeviceTools: () => fuchsiaDeviceTools,
       FuchsiaSdk: () => fuchsiaSdk,
       OperatingSystemUtils: () => osUtils,
@@ -473,7 +473,7 @@ void main() {
       expect(await device.stopApp(app), isTrue);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FuchsiaDeviceTools: () => fuchsiaDeviceTools,
       FuchsiaSdk: () => fuchsiaSdk,
       OperatingSystemUtils: () => osUtils,
@@ -486,7 +486,7 @@ void main() {
       expect(launchResult.hasObservatory, isTrue);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FuchsiaDeviceTools: () => fuchsiaDeviceTools,
       FuchsiaSdk: () => fuchsiaSdk,
       OperatingSystemUtils: () => osUtils,
@@ -499,7 +499,7 @@ void main() {
       expect(launchResult.hasObservatory, isFalse);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FuchsiaDeviceTools: () => fuchsiaDeviceTools,
       FuchsiaSdk: () => fuchsiaSdk,
       OperatingSystemUtils: () => osUtils,
@@ -512,7 +512,7 @@ void main() {
       expect(launchResult.hasObservatory, isTrue);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FuchsiaDeviceTools: () => fuchsiaDeviceTools,
       FuchsiaSdk: () => fuchsiaSdk,
       OperatingSystemUtils: () => osUtils,
@@ -525,7 +525,7 @@ void main() {
       expect(launchResult.hasObservatory, isFalse);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FuchsiaDeviceTools: () => fuchsiaDeviceTools,
       FuchsiaSdk: () => MockFuchsiaSdk(devFinder: FailingDevFinder()),
       OperatingSystemUtils: () => osUtils,
@@ -538,7 +538,7 @@ void main() {
       expect(launchResult.hasObservatory, isFalse);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FuchsiaDeviceTools: () => fuchsiaDeviceTools,
       FuchsiaSdk: () => MockFuchsiaSdk(pm: FailingPM()),
       OperatingSystemUtils: () => osUtils,
@@ -551,7 +551,7 @@ void main() {
       expect(launchResult.hasObservatory, isFalse);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FuchsiaDeviceTools: () => FakeFuchsiaDeviceTools(amber: FailingAmberCtl()),
       FuchsiaSdk: () => fuchsiaSdk,
       OperatingSystemUtils: () => osUtils,
@@ -564,7 +564,7 @@ void main() {
       expect(launchResult.hasObservatory, isFalse);
     }, overrides: <Type, Generator>{
       FileSystem: () => memoryFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FuchsiaDeviceTools: () => FakeFuchsiaDeviceTools(tiles: FailingTilesCtl()),
       FuchsiaSdk: () => fuchsiaSdk,
       OperatingSystemUtils: () => osUtils,

packages/flutter_tools/test/general.shard/intellij/intellij_test.dart

@@ -69,7 +69,7 @@ void main() {
         expect(message.message, contains('recommended minimum version'));
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
       });
 
       testUsingContext('not found', () async {
@@ -90,7 +90,7 @@ void main() {
         expect(message.message, contains('Flutter plugin not installed'));
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
       });
     });
   });

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

@@ -807,7 +807,7 @@ flutter:
     expect(IOSDevice('test').isSupportedForProject(flutterProject), true);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     Platform: () => macPlatform,
   });
   testUsingContext('IOSDevice.isSupportedForProject is true with editable host app', () async {
@@ -819,7 +819,7 @@ flutter:
     expect(IOSDevice('test').isSupportedForProject(flutterProject), true);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     Platform: () => macPlatform,
   });
 
@@ -831,7 +831,7 @@ flutter:
     expect(IOSDevice('test').isSupportedForProject(flutterProject), false);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
     Platform: () => macPlatform,
   });
 }

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

@@ -486,7 +486,7 @@ flutter:
     expect(IOSSimulator('test').isSupportedForProject(flutterProject), true);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
   testUsingContext('IOSDevice.isSupportedForProject is true with editable host app', () async {
@@ -498,7 +498,7 @@ flutter:
     expect(IOSSimulator('test').isSupportedForProject(flutterProject), true);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
   testUsingContext('IOSDevice.isSupportedForProject is false with no host app and no module', () async {
@@ -509,6 +509,6 @@ flutter:
     expect(IOSSimulator('test').isSupportedForProject(flutterProject), false);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 }

packages/flutter_tools/test/general.shard/linux/linux_device_test.dart

@@ -48,7 +48,7 @@ void main() {
     expect(LinuxDevice().isSupportedForProject(flutterProject), true);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
   testUsingContext('LinuxDevice.isSupportedForProject is false with no host app', () async {
@@ -59,7 +59,7 @@ void main() {
     expect(LinuxDevice().isSupportedForProject(flutterProject), false);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
   testUsingContext('LinuxDevice.executablePathForDevice uses the correct package executable', () async {
@@ -76,7 +76,7 @@ void main() {
     expect(LinuxDevice().executablePathForDevice(mockApp, BuildMode.release), releasePath);
   }, overrides: <Type, Generator>{
     FileSystem: () => MemoryFileSystem(),
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 }
 

packages/flutter_tools/test/general.shard/macos/cocoapods_test.dart

@@ -179,7 +179,7 @@ void main() {
       expect(projectUnderTest.ios.podfile.readAsStringSync(), 'Objective-C iOS podfile template');
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('creates swift Podfile if swift', () async {
@@ -195,7 +195,7 @@ void main() {
       expect(projectUnderTest.ios.podfile.readAsStringSync(), 'Swift iOS podfile template');
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       XcodeProjectInterpreter: () => mockXcodeProjectInterpreter,
     });
 
@@ -206,7 +206,7 @@ void main() {
       expect(projectUnderTest.macos.podfile.readAsStringSync(), 'macOS podfile template');
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('does not recreate Podfile when already present', () async {
@@ -218,7 +218,7 @@ void main() {
       expect(projectUnderTest.ios.podfile.readAsStringSync(), 'Existing Podfile');
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('does not create Podfile when we cannot interpret Xcode projects', () async {
@@ -230,7 +230,7 @@ void main() {
       expect(projectUnderTest.ios.podfile.existsSync(), false);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       XcodeProjectInterpreter: () => mockXcodeProjectInterpreter,
     });
 
@@ -256,7 +256,7 @@ void main() {
       expect(releaseContents, contains('Existing release config'));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 
@@ -285,7 +285,7 @@ void main() {
       expect(releaseContents, contains('Existing release config'));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 

packages/flutter_tools/test/general.shard/macos/macos_device_test.dart

@@ -56,7 +56,7 @@ void main() {
       expect(MacOSDevice().isSupportedForProject(flutterProject), true);
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('isSupportedForProject is false with no host app', () async {
@@ -67,7 +67,7 @@ void main() {
       expect(MacOSDevice().isSupportedForProject(flutterProject), false);
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('executablePathForDevice uses the correct package executable', () async {
@@ -84,7 +84,7 @@ void main() {
       expect(MacOSDevice().executablePathForDevice(mockApp, BuildMode.release), releasePath);
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 }

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

@@ -40,7 +40,7 @@ void main() {
         'package:example/main.dart');
   }, overrides: <Type, Generator>{
     FileSystem: () => mockFileSystem,
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
   testUsingContext('single-root maps file from other package to null', () async {
@@ -48,7 +48,7 @@ void main() {
     expect(packageUriMapper.map('/xml/lib/xml.dart'), null);
   }, overrides: <Type, Generator>{
     FileSystem: () => mockFileSystem,
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
   testUsingContext('single-root maps non-main file from same package', () async {
@@ -57,7 +57,7 @@ void main() {
         'package:example/src/foo.dart');
   }, overrides: <Type, Generator>{
     FileSystem: () => mockFileSystem,
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 
   testUsingContext('multi-root maps main file from same package on multiroot scheme', () async {
@@ -76,7 +76,7 @@ void main() {
         'package:example/main.dart');
   }, overrides: <Type, Generator>{
     FileSystem: () => mockFileSystem,
-    ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+    ProcessManager: () => FakeProcessManager.any(),
   });
 }
 

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

@@ -75,7 +75,7 @@ flutter:
       expect(flutterProject.flutterPluginsFile.existsSync(), false);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('Refreshing the plugin list deletes the plugin file when there were plugins but no longer are', () {
@@ -86,7 +86,7 @@ flutter:
       expect(flutterProject.flutterPluginsFile.existsSync(), false);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('Refreshing the plugin list creates a plugin directory when there are plugins', () {
@@ -97,7 +97,7 @@ flutter:
       expect(flutterProject.flutterPluginsFile.existsSync(), true);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('Changes to the plugin list invalidates the Cocoapod lockfiles', () {
@@ -111,7 +111,7 @@ flutter:
       expect(macosProject.podManifestLock.existsSync(), false);
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 
@@ -167,7 +167,7 @@ flutter:
       expect(registrant.readAsStringSync(), contains('class GeneratedPluginRegistrant'));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FeatureFlags: () => featureFlags,
     });
 
@@ -192,7 +192,7 @@ flutter:
       expect(registrant.readAsStringSync(), contains('class GeneratedPluginRegistrant'));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FeatureFlags: () => featureFlags,
     });
 
@@ -288,7 +288,7 @@ plugin3:${pluginUsingOldEmbeddingDir.childDirectory('lib').uri.toString()}
 
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FeatureFlags: () => featureFlags,
       XcodeProjectInterpreter: () => xcodeProjectInterpreter,
     });
@@ -314,7 +314,7 @@ plugin3:${pluginUsingOldEmbeddingDir.childDirectory('lib').uri.toString()}
       expect(registrant.readAsStringSync(), contains('class GeneratedPluginRegistrant'));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FeatureFlags: () => featureFlags,
     });
 
@@ -339,7 +339,7 @@ plugin3:${pluginUsingOldEmbeddingDir.childDirectory('lib').uri.toString()}
       expect(registrant.readAsStringSync(), contains('class GeneratedPluginRegistrant'));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FeatureFlags: () => featureFlags,
     });
 
@@ -364,7 +364,7 @@ plugin3:${pluginUsingOldEmbeddingDir.childDirectory('lib').uri.toString()}
       expect(registrant.readAsStringSync(), contains('class GeneratedPluginRegistrant'));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FeatureFlags: () => featureFlags,
     });
 
@@ -389,7 +389,7 @@ plugin3:${pluginUsingOldEmbeddingDir.childDirectory('lib').uri.toString()}
       expect(registrant.readAsStringSync(), contains('class GeneratedPluginRegistrant'));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       FeatureFlags: () => featureFlags,
     });
   });

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

@@ -36,7 +36,7 @@ void main() {
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('Non-existent files are ignored', () async {
@@ -50,7 +50,7 @@ void main() {
       );
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 }

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

@@ -196,7 +196,7 @@ void main() {
         expectExists(project.macos.managedDirectory.childFile('GeneratedPluginRegistrant.swift'));
       }, overrides: <Type, Generator>{
         FileSystem: () => MemoryFileSystem(),
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         FeatureFlags: () => TestFeatureFlags(isMacOSEnabled: true),
         FlutterProjectFactory: () => FlutterProjectFactory(),
       });
@@ -207,7 +207,7 @@ void main() {
         expectExists(project.macos.generatedXcodePropertiesFile);
       }, overrides: <Type, Generator>{
         FileSystem: () => MemoryFileSystem(),
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         FeatureFlags: () => TestFeatureFlags(isMacOSEnabled: true),
         FlutterProjectFactory: () => FlutterProjectFactory(),
       });
@@ -219,7 +219,7 @@ void main() {
         expectExists(project.linux.managedDirectory.childFile('generated_plugin_registrant.cc'));
       }, overrides: <Type, Generator>{
         FileSystem: () => MemoryFileSystem(),
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         FeatureFlags: () => TestFeatureFlags(isLinuxEnabled: true),
         FlutterProjectFactory: () => FlutterProjectFactory(),
       });
@@ -231,7 +231,7 @@ void main() {
         expectExists(project.windows.managedDirectory.childFile('generated_plugin_registrant.cc'));
       }, overrides: <Type, Generator>{
         FileSystem: () => MemoryFileSystem(),
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         FeatureFlags: () => TestFeatureFlags(isWindowsEnabled: true),
         FlutterProjectFactory: () => FlutterProjectFactory(),
       });
@@ -328,7 +328,7 @@ apply plugin: 'kotlin-android'
         expect(project.android.isKotlin, isTrue);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         XcodeProjectInterpreter: () => mockXcodeProjectInterpreter,
         FlutterProjectFactory: () => flutterProjectFactory,
       });
@@ -349,7 +349,7 @@ apply plugin: 'kotlin-android'
       void testWithMocks(String description, Future<void> testMethod()) {
         testUsingContext(description, testMethod, overrides: <Type, Generator>{
           FileSystem: () => fs,
-          ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+          ProcessManager: () => FakeProcessManager.any(),
           PlistParser: () => mockPlistUtils,
           XcodeProjectInterpreter: () => mockXcodeProjectInterpreter,
           FlutterProjectFactory: () => flutterProjectFactory,
@@ -617,7 +617,7 @@ void testInMemory(String description, Future<void> testMethod()) {
     testMethod,
     overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       Cache: () => Cache(),
       FlutterProjectFactory: () => flutterProjectFactory,
     },

packages/flutter_tools/test/general.shard/runner/flutter_command_runner_test.dart

@@ -67,7 +67,7 @@ void main() {
         expect(versionChecked, isTrue);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: () => platform,
       }, initializeFlutterRoot: false);
 
@@ -79,7 +79,7 @@ void main() {
 
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: () => platform,
       }, initializeFlutterRoot: false);
 
@@ -95,7 +95,7 @@ void main() {
         await runner.run(<String>['dummy', '--local-engine=ios_debug']);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: () => platform,
       }, initializeFlutterRoot: false);
 
@@ -105,7 +105,7 @@ void main() {
         await runner.run(<String>['dummy', '--local-engine-src-path=$_kArbitraryEngineRoot/src', '--local-engine=ios_debug']);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: () => platform,
       }, initializeFlutterRoot: false);
 
@@ -115,7 +115,7 @@ void main() {
         await runner.run(<String>['dummy', '--local-engine=ios_debug']);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: () => platform,
       }, initializeFlutterRoot: false);
     });
@@ -130,7 +130,7 @@ void main() {
 
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       Platform: () => platform,
     }, initializeFlutterRoot: false);
 
@@ -188,7 +188,7 @@ void main() {
         ]);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Platform: () => platform,
       }, initializeFlutterRoot: false);
     });
@@ -201,7 +201,7 @@ void main() {
         expect(fakeCommand.preferences.wrapText, isTrue);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Stdio: () => FakeStdio(hasFakeTerminal: true),
       }, initializeFlutterRoot: false);
 
@@ -212,7 +212,7 @@ void main() {
         expect(fakeCommand.preferences.wrapText, isFalse);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Stdio: () => FakeStdio(hasFakeTerminal: false),
       }, initializeFlutterRoot: false);
 
@@ -223,7 +223,7 @@ void main() {
         expect(fakeCommand.preferences.wrapText, isFalse);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Stdio: () => FakeStdio(hasFakeTerminal: true),
       }, initializeFlutterRoot: false);
 
@@ -234,7 +234,7 @@ void main() {
         expect(fakeCommand.preferences.wrapText, isTrue);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+        ProcessManager: () => FakeProcessManager.any(),
         Stdio: () => FakeStdio(hasFakeTerminal: false),
       }, initializeFlutterRoot: false);
     });

packages/flutter_tools/test/general.shard/runner/runner_test.dart

@@ -71,7 +71,7 @@ void main() {
         'FLUTTER_ROOT': '/',
       }),
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
       Usage: () => CrashingUsage(),
     });
   });

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

@@ -37,7 +37,7 @@ void main() {
       expect(app.packagesFile.path, fs.path.join(projectPath, '.packages'));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 

packages/flutter_tools/test/general.shard/windows/windows_device_test.dart

@@ -49,7 +49,7 @@ void main() {
       expect(WindowsDevice().isSupportedForProject(flutterProject), true);
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('isSupportedForProject is false with no host app', () async {
@@ -60,7 +60,7 @@ void main() {
       expect(WindowsDevice().isSupportedForProject(flutterProject), false);
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
 
     testUsingContext('executablePathForDevice uses the correct package executable', () async {
@@ -77,7 +77,7 @@ void main() {
       expect(WindowsDevice().executablePathForDevice(mockApp, BuildMode.release), releasePath);
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 }

packages/flutter_tools/test/src/fake_process_manager.dart

@@ -9,8 +9,12 @@ import 'package:flutter_tools/src/base/io.dart';
 import 'package:meta/meta.dart';
 import 'package:process/process.dart';
 
+import 'common.dart';
+
 export 'package:process/process.dart' show ProcessManager;
 
+typedef VoidCallback = void Function();
+
 /// A command for [FakeProcessManager].
 @immutable
 class FakeCommand {
@@ -19,28 +23,29 @@ class FakeCommand {
     this.workingDirectory,
     this.environment,
     this.duration = const Duration(),
-    @required this.exitCode,
-    @required this.stdout,
-    @required this.stderr,
+    this.onRun,
+    this.exitCode = 0,
+    this.stdout = '',
+    this.stderr = '',
   }) : assert(command != null),
        assert(duration != null),
+       assert(exitCode != null),
        assert(stdout != null),
        assert(stderr != null);
 
   /// The exact commands that must be matched for this [FakeCommand] to be
-  /// selected from those given to the [FakeProcessManager].
+  /// considered correct.
   final List<String> command;
 
   /// The exact working directory that must be matched for this [FakeCommand] to
-  /// be selected from those given to the [FakeProcessManager].
+  /// be considered correct.
   ///
-  /// If this is null, then it matches any working directory.
+  /// If this is null, the working directory is ignored.
   final String workingDirectory;
 
-  /// The environment that must be matched for this [FakeCommand] to be selected
-  /// from those given to the [FakeProcessManager].
+  /// The environment that must be matched for this [FakeCommand] to be considered correct.
   ///
-  /// If this is null, then it matches any environment.
+  /// If this is null, then the environment is ignored.
   ///
   /// Otherwise, each key in this environment must be present and must have a
   /// value that matches the one given here for the [FakeCommand] to match.
@@ -53,6 +58,10 @@ class FakeCommand {
   /// otherwise the test will be artificially slow.
   final Duration duration;
 
+  /// A callback that is run after [duration] expires but before the [exitCode]
+  /// (and output) are passed back.
+  final VoidCallback onRun;
+
   /// The process' exit code.
   ///
   /// To simulate a never-ending process, set [duration] to a value greated than
@@ -110,13 +119,20 @@ class _FakeProcess implements Process {
   _FakeProcess(
     this._exitCode,
     Duration duration,
+    VoidCallback onRun,
     this.pid,
     this._stderr,
     this.stdin,
     this._stdout,
-  ) : exitCode = Future<void>.delayed(duration).then((void value) => _exitCode),
+  ) : exitCode = Future<void>.delayed(duration).then((void value) {
+        if (onRun != null) {
+          onRun();
+        }
+        return _exitCode;
+      }),
       stderr = Stream<List<int>>.value(utf8.encode(_stderr)),
       stdout = Stream<List<int>>.value(utf8.encode(_stdout));
+
   final int _exitCode;
 
   @override
@@ -145,44 +161,42 @@ class _FakeProcess implements Process {
   }
 }
 
-/// A fake [ProcessManager] which responds to particular commands with particular results.
-///
-/// On creation, pass in a list of [FakeCommand] objects. When the [ProcessManager] methods
-/// such as [start] are invoked, the first matching [FakeCommand] is found and its settings
-/// are used to simulate the result of running that command.
-///
-/// If no command is found, then one is implied which immediately returns exit
-/// code 0 with no output.
-class FakeProcessManager implements ProcessManager {
-  FakeProcessManager(this._commands);
+abstract class FakeProcessManager implements ProcessManager {
+  /// A fake [ProcessManager] which responds to all commands as if they had run
+  /// instantaneously with an exit code of 0 and no output.
+  factory FakeProcessManager.any() = _FakeAnyProcessManager;
 
-  final List<FakeCommand> _commands;
+  /// A fake [ProcessManager] which responds to particular commands with
+  /// particular results.
+  ///
+  /// On creation, pass in a list of [FakeCommand] objects. When the
+  /// [ProcessManager] methods such as [start] are invoked, the next
+  /// [FakeCommand] must match (otherwise the test fails); its settings are used
+  /// to simulate the result of running that command.
+  ///
+  /// If no command is found, then one is implied which immediately returns exit
+  /// code 0 with no output.
+  ///
+  /// There is no logic to ensure that all the listed commands are run. Use
+  /// [FakeCommand.onRun] to set a flag, or specify a sentinel command as your
+  /// last command and verify its execution is successful, to ensure that all
+  /// the specified commands are actually called.
+  factory FakeProcessManager.list(List<FakeCommand> commands) = _SequenceProcessManager;
 
-  FakeCommand _findCommand(List<String> command, String workingDirectory, Map<String, String> environment) {
-    for (FakeCommand candidate in _commands) {
-      if (candidate._matches(command, workingDirectory, environment)) {
-        return candidate;
-      }
-    }
-    return FakeCommand(
-      command: command,
-      workingDirectory: workingDirectory,
-      environment: environment,
-      duration: const Duration(),
-      exitCode: 0,
-      stdout: '',
-      stderr: '',
-    );
-  }
+  FakeProcessManager._();
+
+  @protected
+  FakeCommand findCommand(List<String> command, String workingDirectory, Map<String, String> environment);
 
   int _pid = 9999;
 
   _FakeProcess _runCommand(List<String> command, String workingDirectory, Map<String, String> environment) {
     _pid += 1;
-    final FakeCommand fakeCommand = _findCommand(command, workingDirectory, environment);
+    final FakeCommand fakeCommand = findCommand(command, workingDirectory, environment);
     return _FakeProcess(
       fakeCommand.exitCode,
       fakeCommand.duration,
+      fakeCommand.onRun,
       _pid,
       fakeCommand.stdout,
       null, // stdin
@@ -248,3 +262,41 @@ class FakeProcessManager implements ProcessManager {
     return false;
   }
 }
+
+class _FakeAnyProcessManager extends FakeProcessManager {
+  _FakeAnyProcessManager() : super._();
+
+  @override
+  FakeCommand findCommand(List<String> command, String workingDirectory, Map<String, String> environment) {
+    return FakeCommand(
+      command: command,
+      workingDirectory: workingDirectory,
+      environment: environment,
+      duration: const Duration(),
+      exitCode: 0,
+      stdout: '',
+      stderr: '',
+    );
+  }
+}
+
+class _SequenceProcessManager extends FakeProcessManager {
+  _SequenceProcessManager(this._commands) : super._();
+
+  final List<FakeCommand> _commands;
+
+  @override
+  FakeCommand findCommand(List<String> command, String workingDirectory, Map<String, String> environment) {
+    expect(_commands, isNotEmpty,
+      reason: 'ProcessManager was told to execute $command (in $workingDirectory) '
+              'but the FakeProcessManager.list expected no more processes.'
+    );
+    expect(_commands.first._matches(command, workingDirectory, environment), isTrue,
+      reason: 'ProcessManager was told to execute $command '
+              '(in $workingDirectory, with environment $environment) '
+              'but the next process that was expected was ${_commands.first.command} '
+              '(in ${_commands.first.workingDirectory}, with environment ${_commands.first.environment})}.'
+    );
+    return _commands.removeAt(0);
+  }
+}

packages/flutter_tools/test/src/testbed.dart

@@ -35,7 +35,7 @@ export 'package:flutter_tools/src/base/context.dart' show Generator;
 final Map<Type, Generator> _testbedDefaults = <Type, Generator>{
   // Keeps tests fast by avoiding the actual file system.
   FileSystem: () => MemoryFileSystem(style: platform.isWindows ? FileSystemStyle.windows : FileSystemStyle.posix),
-  ProcessManager: () => FakeProcessManager(<FakeCommand>[]),
+  ProcessManager: () => FakeProcessManager.any(),
   Logger: () => BufferLogger(), // Allows reading logs and prevents stdout.
   OperatingSystemUtils: () => FakeOperatingSystemUtils(),
   OutputPreferences: () => OutputPreferences.test(), // configures BufferLogger to avoid color codes.