def METHOD_NAME(self):
    # --dot set and --output set to filename ending with .json
    # assert that --dot option trumps .json file extension
    stdout = StringIO()
    with temp_output_file(".json") as tmpfname:
        call_command('graph_models', all_applications=True, dot=True, output=tmpfname, stdout=stdout)
        with open(tmpfname, 'r') as outfile:
            foutput = outfile.read()
    assert_looks_like_dotfile(foutput)
    assert stdout.getvalue() == ""