anchor.diff:      });
       SourceEdit edit = getEdit(builder);
       expect(edit.replacement, equalsIgnoringWhitespace('implements A, B'));
  -  }
  -
  -  Future<void> _assertImportLibrary(
  -      String initialCode, List<String> newUris, String expectedCode) async {
  -    String path = convertPath('/home/test/lib/test.dart');
  -    addSource(path, initialCode);
  -    DartChangeBuilderImpl builder = newBuilder();
  -    await builder.addFileEdit(path, (DartFileEditBuilder builder) {
  -      for (String newUri in newUris) {
  -        builder.importLibrary(Uri.parse(newUri));
  -      }
  -    });
  -
  -    String resultCode = initialCode;
  -    List<SourceEdit> edits = getEdits(builder);
  -    for (SourceEdit edit in edits) {
  -      resultCode = edit.apply(resultCode);
  -    }
  -    expect(resultCode, expectedCode);
     }
   
     /**
  
positive.code:     defineReflectiveTests(DartEditBuilderImplTest);
      defineReflectiveTests(DartFileEditBuilderImplTest);
      defineReflectiveTests(DartLinkedEditBuilderImplTest);
    });
  }
  
  
negative.code: @reflectiveTest
  class DartEditBuilderImplTest extends AbstractContextTest
      with BuilderTestMixin {
    test_writeClassDeclaration_interfaces() async {
      String path = convertPath('/home/test/lib/test.dart');
      addSource(path, 'class A {}');
  