audio.play() set a pin mode to `music` instead of `audio`

[microbit-carlos]

To replicate in v2:

>>> frames = [audio.AudioFrame()] * 128
>>> audio.play(frames, pin=pin16, wait=False); pin16.get_mode()
'music'

On V1:

>>> frames = [audio.AudioFrame()] * 128
>>> audio.play(frames, pin=pin16, wait=False); pin16.get_mode()
'audio'

[dpgeorge]

This has been fixed by fd99f40

[dpgeorge]

Note that there are still some differences between v1 and v2 when it comes to pin modes and music/audio/speech. This is mainly because of #50 (comment)

This is a test I used when fixing this issue, that runs on both v1 and v2:

import os
microbit_version = int(os.uname().release[0])

import music
from microbit import pin0, audio

frames = [audio.AudioFrame()] * 128

if microbit_version == 1:
    music.play(music.PYTHON, wait=0)
    assert pin0.get_mode() == "music"
    try:
        audio.play(frames, wait=0)
        assert False
    except Exception as exc:
        assert repr(exc) == "ValueError('Pin 0 in music mode',)"
    assert pin0.get_mode() == "music"
    music.stop()
    assert pin0.get_mode() == "unused"
    audio.play(frames, wait=0)
    assert pin0.get_mode() == "audio", pin0.get_mode()
    audio.stop()
    assert pin0.get_mode() == "unused"
else:
    music.play(music.PYTHON, wait=0)
    assert pin0.get_mode() == "music"
    # allows playing audio while music is playing
    audio.play(frames, wait=0)
    assert pin0.get_mode() == "audio"
    audio.stop()
    # stays in audio mode to prevent clicks
    assert pin0.get_mode() == "audio"

audio.play(frames, wait=0)
assert pin0.get_mode() == "audio"
music.play(music.PYTHON, wait=0)
assert pin0.get_mode() == "music"
music.stop()
if microbit_version == 1:
    assert pin0.get_mode() == "unused"
else:
    # stays in music mode to prevent clicks
    assert pin0.get_mode() == "music"

print("Test passed")

Notice that the test needs very different logic for v1 and v2.