audio: fix GetDefault???Device API call

amodem/audio.py

@@ -62,7 +62,13 @@ class Stream(object):
         self.bytes_per_sample = config.sample_size
         assert config.bits_per_sample == 16  # just to make sure :)
 
-        index = lib.call('GetDefaultInputDevice', restype=ctypes.c_int)
+        read = bool(read)
+        write = bool(write)
+        assert read != write
+
+        direction = 'Input' if read else 'Output'
+        api_name = 'GetDefault{0}Device'.format(direction)
+        index = lib.call(api_name, restype=ctypes.c_int)
         self.params = Stream.Parameters(
             device=index,               # choose default device
             channelCount=1,             # mono audio

tests/test_audio.py

@@ -10,7 +10,8 @@ def test():
     with mock.patch('ctypes.CDLL') as cdll:
         lib = mock.Mock()
         lib.Pa_GetErrorText = lambda code: 'Error' if code else 'Success'
-        lib.Pa_GetDefaultInputDevice.return_value = 1
+        lib.Pa_GetDefaultOutputDevice.return_value = 1
+        lib.Pa_GetDefaultInputDevice.return_value = 2
         lib.Pa_OpenStream.return_value = 0
         cdll.return_value = lib
         interface = audio.Interface(
@@ -18,12 +19,14 @@ def test():
         )
         with interface:
             s = interface.player()
+            assert s.params.device == 1
             s.stream = 1  # simulate non-zero output stream handle
             s.write(data=data)
             s.close()
 
         with interface:
             s = interface.recorder()
+            assert s.params.device == 2
             s.stream = 2  # simulate non-zero input stream handle
             s.read(len(data))
             s.close()