anchor.diff:    @override
     void setUp() {
       super.setUp();
  +    wasTaskModelEnabled = AnalysisEngine.instance.useTaskModel;
  +    AnalysisEngine.instance.useTaskModel = true;
       createProject();
       analysisDomain = handler;
       completionDomain = new Test_CompletionDomainHandler(server);
  
positive.code:   int requestCount = 0;
    String testFile2 = '/project/bin/test2.dart';
  
    AnalysisServer createAnalysisServer(Index index) {
      ExtensionManager manager = new ExtensionManager();
      ServerPlugin serverPlugin = new ServerPlugin();
  
negative.code:     super.tearDown();
      analysisDomain = null;
      completionDomain = null;
      AnalysisEngine.instance.useTaskModel = wasTaskModelEnabled;
    }
  
    /**
  