'Fixed' test_mock_pin_frequency_unsupported
'Fixed' test_mock_pin_frequency_unsupported

See the discussion at https://github.com/RPi-Distro/python-gpiozero/issues/206#issuecomment-186289488
waveform80/gpio-zero,RPi-Distro/python-gpiozero,lurch/python-gpiozero,MrHarcombe/python-gpiozero