Add volume_step property to MediaPlayerEntity (#105574)

* Add volume_step property to MediaPlayerEntity

* Improve tests

* Address review comments

homeassistant/components/media_player/__init__.py

@@ -454,6 +454,7 @@ class MediaPlayerEntityDescription(EntityDescription):
     """A class that describes media player entities."""
 
     device_class: MediaPlayerDeviceClass | None = None
+    volume_step: float | None = None
 
 
 class MediaPlayerEntity(Entity):
@@ -505,6 +506,7 @@ class MediaPlayerEntity(Entity):
     _attr_state: MediaPlayerState | None = None
     _attr_supported_features: MediaPlayerEntityFeature = MediaPlayerEntityFeature(0)
     _attr_volume_level: float | None = None
+    _attr_volume_step: float
 
     # Implement these for your media player
     @property
@@ -533,6 +535,18 @@ class MediaPlayerEntity(Entity):
         """Volume level of the media player (0..1)."""
         return self._attr_volume_level
 
+    @property
+    def volume_step(self) -> float:
+        """Return the step to be used by the volume_up and volume_down services."""
+        if hasattr(self, "_attr_volume_step"):
+            return self._attr_volume_step
+        if (
+            hasattr(self, "entity_description")
+            and (volume_step := self.entity_description.volume_step) is not None
+        ):
+            return volume_step
+        return 0.1
+
     @property
     def is_volume_muted(self) -> bool | None:
         """Boolean if volume is currently muted."""
@@ -956,7 +970,9 @@ class MediaPlayerEntity(Entity):
             and self.volume_level < 1
             and self.supported_features & MediaPlayerEntityFeature.VOLUME_SET
         ):
-            await self.async_set_volume_level(min(1, self.volume_level + 0.1))
+            await self.async_set_volume_level(
+                min(1, self.volume_level + self.volume_step)
+            )
 
     async def async_volume_down(self) -> None:
         """Turn volume down for media player.
@@ -972,7 +988,9 @@ class MediaPlayerEntity(Entity):
             and self.volume_level > 0
             and self.supported_features & MediaPlayerEntityFeature.VOLUME_SET
         ):
-            await self.async_set_volume_level(max(0, self.volume_level - 0.1))
+            await self.async_set_volume_level(
+                max(0, self.volume_level - self.volume_step)
+            )
 
     async def async_media_play_pause(self) -> None:
         """Play or pause the media player."""

tests/components/media_player/test_async_helpers.py

@@ -10,6 +10,7 @@ from homeassistant.const import (
     STATE_PLAYING,
     STATE_STANDBY,
 )
+from homeassistant.core import HomeAssistant
 
 
 class ExtendedMediaPlayer(mp.MediaPlayerEntity):
@@ -148,28 +149,64 @@ class SimpleMediaPlayer(mp.MediaPlayerEntity):
         self._state = STATE_STANDBY
 
 
+class AttrMediaPlayer(SimpleMediaPlayer):
+    """Media player setting properties via _attr_*."""
+
+    _attr_volume_step = 0.2
+
+
+class DescrMediaPlayer(SimpleMediaPlayer):
+    """Media player setting properties via entity description."""
+
+    entity_description = mp.MediaPlayerEntityDescription(key="test", volume_step=0.3)
+
+
 @pytest.fixture(params=[ExtendedMediaPlayer, SimpleMediaPlayer])
 def player(hass, request):
     """Return a media player."""
     return request.param(hass)
 
 
-async def test_volume_up(player) -> None:
+@pytest.mark.parametrize(
+    ("player_class", "volume_step"),
+    [
+        (ExtendedMediaPlayer, 0.1),
+        (SimpleMediaPlayer, 0.1),
+        (AttrMediaPlayer, 0.2),
+        (DescrMediaPlayer, 0.3),
+    ],
+)
+async def test_volume_up(
+    hass: HomeAssistant, player_class: type[mp.MediaPlayerEntity], volume_step: float
+) -> None:
     """Test the volume_up and set volume methods."""
+    player = player_class(hass)
     assert player.volume_level == 0
     await player.async_set_volume_level(0.5)
     assert player.volume_level == 0.5
     await player.async_volume_up()
-    assert player.volume_level == 0.6
+    assert player.volume_level == 0.5 + volume_step
 
 
-async def test_volume_down(player) -> None:
+@pytest.mark.parametrize(
+    ("player_class", "volume_step"),
+    [
+        (ExtendedMediaPlayer, 0.1),
+        (SimpleMediaPlayer, 0.1),
+        (AttrMediaPlayer, 0.2),
+        (DescrMediaPlayer, 0.3),
+    ],
+)
+async def test_volume_down(
+    hass: HomeAssistant, player_class: type[mp.MediaPlayerEntity], volume_step: float
+) -> None:
     """Test the volume_down and set volume methods."""
+    player = player_class(hass)
     assert player.volume_level == 0
     await player.async_set_volume_level(0.5)
     assert player.volume_level == 0.5
     await player.async_volume_down()
-    assert player.volume_level == 0.4
+    assert player.volume_level == 0.5 - volume_step
 
 
 async def test_media_play_pause(player) -> None: