anchor.diff:  
       test('invalid setBreakpoint throws exception', () async {
         await env.setupEnvironment();
  -      // Service with more than 1 registration.
  -      serviceManager.registeredMethodsForService.putIfAbsent(
  -        'fakeMethod',
  -        () => ['registration1.fakeMethod', 'registration2.fakeMethod'],
  -      );
  -      expect(serviceManager.callService('fakeMethod'), throwsException);
  -
  -      final Completer<Object> testDone = Completer();
  -      Object testError;
  -      runZoned(() {
  -        Future<void> asyncTestMethod() async {
  -          // Service with less than 1 registration.
  -          expect(
  -              serviceManager.service.addBreakpoint(
  -                  serviceManager.isolateManager.selectedIsolate.id,
  -                  'fake-script-id',
  -                  1),
  -              throwsException);
  -
  -          await env.tearDownEnvironment();
  -        }
  -
  -        testDone.complete(asyncTestMethod());
  -      }, onError: ([error]) {
  -        testError = error;
  -      });
  -      await testDone.future;
  -      // Verify that no uncaught exceptions were thrown in an async manner
  -      // while running the test.
  -      // This case catches a regression where a setting a breakpoint at an
  -      // invalid line would throw an uncaught exception.
  -      expect(testError, isNull);
  +
  +      await expectLater(
  +        serviceManager.service.addBreakpoint(
  +            serviceManager.isolateManager.selectedIsolate.id,
  +            'fake-script-id',
  +            1),
  +        throwsA(const TypeMatcher<RPCError>()
  +            .having((e) => e.code, 'code', equals(jsonRpcInvalidParamsCode))),
  +      );
  +
  +      await env.tearDownEnvironment();
       });
   
       test('toggle boolean service extension', () async {
  
positive.code:     test('callMulticastService throws exception', () async {
        await env.setupEnvironment();
  
        expect(serviceManager.callService('fakeMethod'), throwsException);
  
        await env.tearDownEnvironment();
      });
  
negative.code:       await env.setupEnvironment();
  
        // Service with less than 1 registration.
        await expectLater(
            serviceManager.callService('fakeMethod'), throwsException);
  
        // Service with more than 1 registration.
        serviceManager.registeredMethodsForService.putIfAbsent('fakeMethod',
            () => ['registration1.fakeMethod', 'registration2.fakeMethod']);
        await expectLater(
            serviceManager.callService('fakeMethod'), throwsException);
  
        await env.tearDownEnvironment();
      });
  