def test_log_output_when_error_display_false(self): warn_string = 'warn_string' error_file = '/tmp/a' with patch('sys.stdout', new=io.StringIO()) as fake_out: jo = JsonOutput(error_log=error_file) jo.error_log = io.StringIO() jo.warn(warn_string) file_output = jo.error_log.getvalue() standard_out = fake_out.getvalue() assert standard_out == "" assert warn_string in file_output