anchor.diff:          });
         });
       });
  -    asyncTestStarted();
     }
   
     static void testRenameSync() {
  
positive.code:         });
        });
      });
      asyncTestStarted();
    }
  
    // Test for file read and write functionality.
    static void testOutputStreamWriteString() {
      String content = "foobar";
      String filename = tempDirectory.path + "/outstream_write_string";
      File file = new File(filename);
  
negative.code: 
    // Test for file read and write functionality.
    static void testReadWrite() {
      asyncTestStarted();
      // Read a file.
      String inFilename = getFilename("tests/vm/data/fixed_length_file");
      final File file = new File(inFilename);
  