anchor.diff:        String annotationText,
         validator(SimpleIdentifier name1, SimpleIdentifier name2,
             SimpleIdentifier name3, Element annotationElement)) async {
  -    CompilationUnit unit = await resolveSource('''
  +    addTestFile('''
   import 'a.dart' $annotationPrefix;
   $annotationText
   class C {}
   ''');
  -    var clazz = unit.declarations.single as ClassDeclaration;
  +    await resolveTestFile();
  +
  +    var clazz = findNode.classDeclaration('C');
       Annotation annotation = clazz.metadata.single;
       Identifier name = annotation.name;
       Element annotationElement = annotation.element;
  
positive.code:     });
    }
  
    test_annotation_class_staticConstField() async {
      addNamedSource('/a.dart', r'''
  class A {
    static const V = 0;
  }
  
negative.code:     });
    }
  
    test_class_prefixed_namedConstructor() async {
      newFile('/test/lib/a.dart', content: r'''
  class A {
    const A.named();
  }
  