anchor.diff:    test_analysisOptions_excludes() async {
       await drive('data/exclude_test_project',
           options: 'data/exclude_test_project/$optionsFileName');
  -    _expectUndefinedClassErrorsWithoutExclusions(usePreviewDart2);
  +    _expectUndefinedClassErrorsWithoutExclusions();
     }
   
     test_analysisOptions_excludesRelativeToAnalysisOptions_explicit() async {
  
positive.code:     // has to then understand that.
      await drive('data/exclude_test_project',
          options: 'data/exclude_test_project/$optionsFileName');
      _expectUndefinedClassErrorsWithoutExclusions(usePreviewDart2);
    }
  
    test_analysisOptions_excludesRelativeToAnalysisOptions_inferred() async {
  
negative.code:     // analysis_options above lib. The exclude is relative to the project, not
      // the analyzed path, and it has to then understand that.
      await drive('data/exclude_test_project/lib', options: null);
      _expectUndefinedClassErrorsWithoutExclusions();
    }
  
    test_analyzeFilesInDifferentContexts() async {
  