code: @Test public void renameParentDirectoryTest() throws IOException {
    StringBuilder toCompare=new StringBuilder();
    mFsShell.mkdir(new String[]{"mkdir","/test/File1"});
    toCompare.append(getCommandOutput(new String[]{"mkdir","/test/File1"}));
    mFsShell.rename(new String[]{"rename","/test","/test2"});
    toCompare.append(getCommandOutput(new String[]{"mv","/test","/test2"}));
    Assert.assertNotNull(mTfs.getFile("/test2/File1"));
    Assert.assertNull(mTfs.getFile("/test"));
    Assert.assertNull(mTfs.getFile("/test/File1"));
    Assert.assertEquals(toCompare.toString(),mOutput.toString());
  }
  