audio: add simple ALSA interface

tests/test_alsa.py

@@ -0,0 +1,40 @@
+from amodem import alsa, config
+
+import mock
+
+
+def test_alsa():
+    interface = alsa.Interface(config=config.fastest())
+    interface.launch = mock.Mock()
+    with interface:
+        r = interface.recorder()
+        r.read(2)
+        r.close()
+
+    p = mock.call(
+        args='arecord -f S16_LE -c 1 -r 32000 -T 100 -q -'.split(),
+        stdout=-1)
+    assert interface.launch.mock_calls == [p, p.stdout.read(2), p.kill()]
+
+    interface.launch = mock.Mock()
+    with interface:
+        p = interface.player()
+        p.write('\x00\x00')
+        p.close()
+
+    p = mock.call(
+        args='aplay -f S16_LE -c 1 -r 32000 -T 100 -q -'.split(),
+        stdin=-1)
+    assert interface.launch.mock_calls == [
+        p, p.stdin.write('\x00\x00'), p.stdin.close(), p.wait()
+    ]
+
+
+def test_alsa_subprocess():
+    interface = alsa.Interface(config=config.fastest())
+    with mock.patch('subprocess.Popen') as popen:
+        with interface:
+            p = interface.launch(args=['foobar'])
+            p.wait.side_effect = OSError('invalid command')
+            assert interface.processes == [p]
+            assert popen.mock_calls == [mock.call(args=['foobar'])]