anchor.diff:        // simulate package
         await _createPackage(fs, 'somepkg', 'somefile.txt');
   
  -      devFS = DevFS(vmService, 'test', tempDir);
         await devFS.create();
         vmService.expectMessages(<String>['create test']);
         expect(devFS.assetPathsToEvict, isEmpty);
  
positive.code:         return Future<HttpClientResponse>.value(httpClientResponse);
        });
  
        devFS = DevFS(vmService, 'test', tempDir);
        await devFS.create();
  
        final MockResidentCompiler residentCompiler = MockResidentCompiler();
  
negative.code: 
        // simulate package
        await _createPackage(fs, 'somepkg', 'somefile.txt');
        await devFS.create();
        vmService.expectMessages(<String>['create test']);
        expect(devFS.assetPathsToEvict, isEmpty);
  