tests: Make dummy backend use real playback provider if audio is passed in

This is needed in order to make audio events propagate, to core and trigger
async state changes in tests.

tests/dummy_backend.py

@@ -22,7 +22,10 @@ class DummyBackend(pykka.ThreadingActor, backend.Backend):
         super(DummyBackend, self).__init__()
 
         self.library = DummyLibraryProvider(backend=self)
-        self.playback = DummyPlaybackProvider(audio=audio, backend=self)
+        if audio:
+            self.playback = backend.PlaybackProvider(audio=audio, backend=self)
+        else:
+            self.playback = DummyPlaybackProvider(audio=audio, backend=self)
         self.playlists = DummyPlaylistsProvider(backend=self)
 
         self.uri_schemes = ['dummy']

tests/mpd/protocol/__init__.py

@@ -10,7 +10,7 @@ from mopidy import core
 from mopidy.internal import deprecation
 from mopidy.mpd import session, uri_mapper
 
-from tests import dummy_backend, dummy_mixer
+from tests import dummy_audio, dummy_backend, dummy_mixer
 
 
 class MockConnection(mock.Mock):
@@ -44,11 +44,13 @@ class BaseTestCase(unittest.TestCase):
             self.mixer = dummy_mixer.create_proxy()
         else:
             self.mixer = None
-        self.backend = dummy_backend.create_proxy()
+        self.audio = dummy_audio.create_proxy()
+        self.backend = dummy_backend.create_proxy(audio=self.audio)
 
         with deprecation.ignore():
             self.core = core.Core.start(
                 self.get_config(),
+                audio=self.audio,
                 mixer=self.mixer,
                 backends=[self.backend]).proxy()
 

tests/mpd/protocol/test_regression.py

@@ -31,6 +31,7 @@ class IssueGH17RegressionTest(protocol.BaseTestCase):
             Track(uri='dummy:e'),
             Track(uri='dummy:f'),
         ]
+        self.audio.trigger_fake_playback_failure('dummy:error')
         self.backend.library.dummy_library = tracks
         self.core.tracklist.add(uris=[t.uri for t in tracks]).get()