code: @Test public void renameTest() throws IOException {
    StringBuilder toCompare=new StringBuilder();
    mFsShell.mkdir(new String[]{"mkdir","/testFolder1"});
    toCompare.append(getCommandOutput(new String[]{"mkdir","/testFolder1"}));
    Assert.assertNotNull(mTfs.getFile("/testFolder1"));
    mFsShell.rename(new String[]{"rename","/testFolder1","/testFolder"});
    toCompare.append(getCommandOutput(new String[]{"mv","/testFolder1","/testFolder"}));
    Assert.assertEquals(toCompare.toString(),mOutput.toString());
    Assert.assertNotNull(mTfs.getFile("/testFolder"));
    Assert.assertNull(mTfs.getFile("/testFolder1"));
  }
  