cli: toggle shuffle

fixes #197

test/test_commands.py

@@ -11,7 +11,12 @@ import pytest
 async def test_commands(bus_address):
     [mpris] = await setup_mpris('commands', bus_address=bus_address)
 
+    mpris.shuffle = False
+    mpris.volume = 1.0
+    mpris.loop_status = 'Track'
+
     commands = ('play', 'pause', 'play-pause', 'stop', 'next', 'previous')
+    setters = ('volume 0.8', 'loop playlist', 'shuffle on')
 
     def get_called(cmd):
         return getattr(mpris, f'{cmd.replace("-", "_")}_called')
@@ -19,8 +24,16 @@ async def test_commands(bus_address):
     playerctl = PlayerctlCli(bus_address)
 
     results = await asyncio.gather(*(playerctl.run(f'-p commands {cmd}')
-                                     for cmd in commands))
+                                     for cmd in commands + setters))
 
-    for i, result in enumerate(results):
-        cmd = commands[i]
+    for i, cmd in enumerate(commands):
+        result = results[i]
         assert get_called(cmd), f'{cmd} was not called: {result.stderr}'
+
+    assert mpris.shuffle
+    assert mpris.volume == 0.8
+    assert mpris.loop_status == 'Playlist'
+
+    await playerctl.run('-p commands shuffle toggle')
+
+    assert not mpris.shuffle