anchor.diff:  class MockXcode extends Mock implements Xcode {}
   class MockFile extends Mock implements File {}
   class MockPortForwarder extends Mock implements DevicePortForwarder {}
  +class MockUsage extends Mock implements Usage {}
   
   void main() {
     final FakePlatform macPlatform = FakePlatform.fromPlatform(const LocalPlatform());
  
positive.code:           debuggingOptions: DebuggingOptions.enabled(const BuildInfo(BuildMode.debug, null)),
            platformArgs: <String, dynamic>{},
          );
          expect(launchResult.started, isTrue);
          expect(launchResult.hasObservatory, isTrue);
          expect(await device.stopApp(mockApp), isFalse);
  
negative.code:         MDnsObservatoryDiscovery: () => mockMDnsObservatoryDiscovery,
          Platform: () => macPlatform,
          ProcessManager: () => mockProcessManager,
          Usage: () => mockUsage,
        });
  
        testUsingContext(' succeeds in debug mode when mDNS fails by falling back to manual protocol discovery', () async {
  