feat: add microphone selection utils

Providing two functions, one to choose the default microphone, the other to choose a microphone interactively. With tests.

ref: N25B-119

src/robot_interface/utils/microphone.py

@@ -0,0 +1,54 @@
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+def choose_mic_interactive(audio):
+    """
+    Choose a microphone to use, interactively in the CLI.
+
+    :param audio: An instance of PyAudio to use.
+    :type audio: pyaudio.PyAudio
+
+    :return: A dictionary from PyAudio containing information about the microphone to use, or None
+    if there is no microphone.
+    :rtype: dict | None
+    """
+    device_count = audio.get_device_count()
+    if device_count == 0: return None
+
+    print("Found {} audio devices:".format(device_count))
+    for i in range(device_count):
+        print("- {}: {}".format(i, audio.get_device_info_by_index(i)["name"]))
+
+    microphone_index = None
+    while microphone_index is None:
+        chosen = raw_input("Which device would you like to use?\n> ")
+        try:
+            chosen = int(chosen)
+            if chosen < 0 or chosen >= device_count: raise ValueError()
+            microphone_index = chosen
+        except ValueError:
+            print("Please enter a number between 0 and {}".format(device_count-1))
+
+    chosen_microphone = audio.get_device_info_by_index(microphone_index)
+    logger.info("Chose microphone \"{}\"".format(chosen_microphone["name"]))
+    return chosen_microphone
+
+
+def choose_mic_default(audio):
+    """
+    Get the system's default microphone to use.
+
+    :param audio: An instance of PyAudio to use.
+    :type audio: pyaudio.PyAudio
+
+    :return: A dictionary from PyAudio containing information about the microphone to use, or None
+    if there is no microphone.
+    :rtype: dict | None
+    """
+    device_count = audio.get_device_count()
+    if device_count == 0: return None
+
+    default_device = audio.get_default_input_device_info()
+    return default_device

test/unit/test_microphone_utils.py

@@ -0,0 +1,107 @@
+import functools
+import random
+from StringIO import StringIO
+import sys
+
+import pyaudio
+import pytest
+
+from robot_interface.utils.microphone import choose_mic_default, choose_mic_interactive
+
+
+@pytest.fixture
+def pyaudio_instance():
+    audio = pyaudio.PyAudio()
+    yield audio
+
+
+def test_choose_mic_default(pyaudio_instance):
+    """
+    The result must contain at least "index", as this is used to identify the microphone.
+    The "name" is used for logging, so it should also exist.
+    It must have one or more channels.
+    Lastly it must be capable of sending at least 16000 samples per second.
+    """
+    result = choose_mic_default(pyaudio_instance)
+    assert "index" in result
+    assert isinstance(result["index"], long)
+
+    assert "name" in result
+    assert isinstance(result["name"], (str, unicode))
+
+    assert "maxInputChannels" in result
+    assert isinstance(result["maxInputChannels"], long)
+    assert result["maxInputChannels"] > 0
+
+    assert "defaultSampleRate" in result
+    assert isinstance(result["defaultSampleRate"], float)
+    assert result["defaultSampleRate"] >= 16000
+
+
+def test_choose_mic_interactive_input_not_int(pyaudio_instance, mocker):
+    """
+    First mock an input that's not an integer, then a valid integer. There should be no errors.
+    """
+    mock_input = mocker.patch("__builtin__.raw_input", side_effect=["not an integer", "0"])
+    fake_out = StringIO()
+    mocker.patch.object(sys, "stdout", fake_out)
+
+    result = choose_mic_interactive(pyaudio_instance)
+    assert "index" in result
+    assert isinstance(result["index"], (int, long))
+    assert result["index"] == 0
+
+    assert mock_input.called
+
+    assert any(p.startswith("Please enter a number") for p in fake_out.getvalue().splitlines())
+
+
+def test_choose_mic_interactive_negative_index(pyaudio_instance, mocker):
+    """
+    Make sure that the interactive method does not allow negative integers as input.
+    """
+    mock_input = mocker.patch("__builtin__.raw_input", side_effect=["-1", "0"])
+    fake_out = StringIO()
+    mocker.patch.object(sys, "stdout", fake_out)
+
+    result = choose_mic_interactive(pyaudio_instance)
+    assert "index" in result
+    assert isinstance(result["index"], (int, long))
+    assert result["index"] == 0
+
+    assert mock_input.called
+
+    assert any(p.startswith("Please enter a number") for p in fake_out.getvalue().splitlines())
+
+
+def test_choose_mic_interactive_index_too_high(pyaudio_instance, mocker):
+    """
+    Make sure that the interactive method does not allow indices higher than the highest mic index.
+    """
+    real_count = pyaudio_instance.get_device_count()
+    mock_input = mocker.patch("__builtin__.raw_input", side_effect=[str(real_count), "0"])
+    fake_out = StringIO()
+    mocker.patch.object(sys, "stdout", fake_out)
+
+    result = choose_mic_interactive(pyaudio_instance)
+    assert "index" in result
+    assert isinstance(result["index"], (int, long))
+    assert result["index"] == 0
+
+    assert mock_input.called
+
+    assert any(p.startswith("Please enter a number") for p in fake_out.getvalue().splitlines())
+
+
+def test_choose_mic_interactive_random_index(pyaudio_instance, mocker):
+    """
+    Get a random index from the list of available mics, make sure it's correct.
+    """
+    real_count = pyaudio_instance.get_device_count()
+    random_index = random.randrange(real_count)
+    mocker.patch("__builtin__.raw_input", side_effect=[str(random_index)])
+
+    result = choose_mic_interactive(pyaudio_instance)
+    assert "index" in result
+    assert isinstance(result["index"], (int, long))
+    assert result["index"] == random_index