anchor.diff:                            file4.deleteHandler = () {
                               file4.existsHandler = (exists) {
                                 Expect.isFalse(exists);
  -                              asyncTestDone();
  +                              asyncTestDone("testReadWrite");
                               };
                               file4.exists();
                             };
  
positive.code:                       file.deleteHandler = () {
                          file.existsHandler = (exists) {
                            Expect.isFalse(exists);
                            asyncTestDone();
                          };
                          file.exists();
                        };
  
negative.code:         testAppendSync();
          testWriteAppend();
          testOutputStreamWriteAppend();
        });
    }
  }
  