anchor.diff:              ..setLastModifiedSync(DateTime(2002));
           }
         ),
  +      const FakeCommand(
  +        command: <String>[
  +          '/bin/cache/dart-sdk/bin/pub',
  +          '--verbosity=warning',
  +          'get',
  +          '--no-precompile',
  +        ],
  +      ),
       ]);
  -    Testbed().run(() async {
  +    await Testbed().run(() async {
         // the good scenario: .packages is old, pub updates the file.
         fs.file('.packages')
           ..createSync()
  
positive.code:     Pub: () => const Pub(),
    });
  
    test('Pub error handling', () {
      final MemoryFileSystem fileSystem = MemoryFileSystem();
      final FakeProcessManager processManager = FakeProcessManager.list(<FakeCommand>[
        FakeCommand(
  
negative.code:         await pub.get(context: PubContext.flutterTests, checkLastModified: true);
          expect(true, isFalse, reason: 'pub.get did not throw');
        } catch (error) {
          expect(error, isInstanceOf<Exception>());
          expect(error.message, '/: unexpected concurrent modification of pubspec.yaml while running pub.');
        }
        expect(testLogger.statusText, 'Running "flutter pub get" in /...\n');
  