feat: Add iTunes Store Identifier to metadata

- Added `iTunesStoreIdentifier` to `FeatureName` in `pyatv/const.py`.
- Updated `Playing` class in `pyatv/interface.py` to include `itunes_store_identifier`.
- Enhanced the `metadata_field` function in `pyatv/protocols/mrp/__init__.py` to support `itunes_store_identifier`.
- Adjusted fake device implementation in `tests/fake_device/mrp.py` to handle `itunes_store_identifier`.
- Updated functional tests in `tests/protocols/mrp/test_mrp_functional.py` to verify `itunes_store_identifier`.
- Modified documentation to include `itunes_store_identifier`.

docs/api/pyatv.const.html

@@ -48,7 +48,7 @@ <h4><code><a title="pyatv.const.DeviceState" href="#pyatv.const.DeviceState">Dev
 </li>
 <li>
 <h4><code><a title="pyatv.const.FeatureName" href="#pyatv.const.FeatureName">FeatureName</a></code></h4>
-<ul class="two-column">
+<ul class="">
 <li><code><a title="pyatv.const.FeatureName.AccountList" href="#pyatv.const.FeatureName.AccountList">AccountList</a></code></li>
 <li><code><a title="pyatv.const.FeatureName.Action" href="#pyatv.const.FeatureName.Action">Action</a></code></li>
 <li><code><a title="pyatv.const.FeatureName.AddOutputDevices" href="#pyatv.const.FeatureName.AddOutputDevices">AddOutputDevices</a></code></li>
@@ -114,6 +114,7 @@ <h4><code><a title="pyatv.const.FeatureName" href="#pyatv.const.FeatureName">Fea
 <li><code><a title="pyatv.const.FeatureName.VolumeDown" href="#pyatv.const.FeatureName.VolumeDown">VolumeDown</a></code></li>
 <li><code><a title="pyatv.const.FeatureName.VolumeUp" href="#pyatv.const.FeatureName.VolumeUp">VolumeUp</a></code></li>
 <li><code><a title="pyatv.const.FeatureName.WakeUp" href="#pyatv.const.FeatureName.WakeUp">WakeUp</a></code></li>
+<li><code><a title="pyatv.const.FeatureName.iTunesStoreIdentifier" href="#pyatv.const.FeatureName.iTunesStoreIdentifier">iTunesStoreIdentifier</a></code></li>
 </ul>
 </li>
 <li>
@@ -223,7 +224,7 @@ <h1 class="title">Module <code>pyatv.const</code></h1>
 </header>
 <section id="section-intro">
 <p>Constants used in the public API.</p>
-<div class="git-link-div"><a href="https://github.com/postlund/pyatv/blob/master/pyatv/const.py#L1-L454" class="git-link">Browse git</a></div>
+<div class="git-link-div"><a href="https://github.com/postlund/pyatv/blob/master/pyatv/const.py#L1-L457" class="git-link">Browse git</a></div>
 </section>
 <section>
 </section>
@@ -348,7 +349,7 @@ <h3>Class variables</h3>
 </code></dt>
 <dd>
 <section class="desc"><p>All supported features.</p></section>
-<div class="git-link-div"><a href="https://github.com/postlund/pyatv/blob/master/pyatv/const.py#L249-L445" class="git-link">Browse git</a></div>
+<div class="git-link-div"><a href="https://github.com/postlund/pyatv/blob/master/pyatv/const.py#L249-L448" class="git-link">Browse git</a></div>
 <h3>Ancestors</h3>
 <ul class="hlist">
 <li>enum.Enum</li>
@@ -615,6 +616,10 @@ <h3>Class variables</h3>
 <dd>
 <section class="desc"><p>Wake up device (deprecated; use Power.turn_on).</p></section>
 </dd>
+<dt id="pyatv.const.FeatureName.iTunesStoreIdentifier"><code class="name">var <span class="ident">iTunesStoreIdentifier</span> = 50</code></dt>
+<dd>
+<section class="desc"><p>iTunes Store Identifier for Content</p></section>
+</dd>
 </dl>
 </dd>
 <dt id="pyatv.const.FeatureState"><code class="flex name class">
@@ -931,7 +936,7 @@ <h3>Class variables</h3>
 </code></dt>
 <dd>
 <section class="desc"><p>Touch action constants.</p></section>
-<div class="git-link-div"><a href="https://github.com/postlund/pyatv/blob/master/pyatv/const.py#L448-L454" class="git-link">Browse git</a></div>
+<div class="git-link-div"><a href="https://github.com/postlund/pyatv/blob/master/pyatv/const.py#L451-L457" class="git-link">Browse git</a></div>
 <h3>Ancestors</h3>
 <ul class="hlist">
 <li>enum.Enum</li>

pyatv/const.py

@@ -363,6 +363,9 @@ class FeatureName(Enum):
     ContentIdentifier = 47
     """Identifier for Content"""
 
+    iTunesStoreIdentifier = 50
+    """iTunes Store Identifier for Content"""
+
     AppList = 38
     """List of launchable apps."""
 

pyatv/interface.py

@@ -475,6 +475,7 @@ class Playing(ABC):
         "season_number",
         "episode_number",
         "content_identifier",
+        "itunes_store_identifier",
     ]
 
     def __init__(  # pylint: disable=too-many-locals
@@ -494,8 +495,10 @@ def __init__(  # pylint: disable=too-many-locals
         season_number: Optional[int] = None,
         episode_number: Optional[int] = None,
         content_identifier: Optional[str] = None,
+        itunes_store_identifier: Optional[int] = None,
     ) -> None:
         """Initialize a new Playing instance."""
+        self._itunes_store_identifier = None
         self._media_type = media_type
         self._device_state = device_state
         self._title = title
@@ -511,6 +514,8 @@ def __init__(  # pylint: disable=too-many-locals
         self._season_number = season_number
         self._episode_number = episode_number
         self._content_identifier = content_identifier
+        self._itunes_store_identifier = itunes_store_identifier
+
         self._post_process()
 
     def _post_process(self) -> None:
@@ -570,6 +575,8 @@ def __str__(self) -> str:  # pylint: disable=too-many-branches
         if self.shuffle is not None:
             output.append(f"     Shuffle: {convert.shuffle_str(self.shuffle)}")
 
+        if self._itunes_store_identifier is not None:
+            output.append(f"iTunes Store Identifier: {self._itunes_store_identifier}")
         return "\n".join(output)
 
     def __eq__(self, other) -> bool:
@@ -676,6 +683,12 @@ def content_identifier(self) -> Optional[str]:
         """Content identifier (app specific)."""
         return self._content_identifier
 
+    @property  # type: ignore
+    @feature(50, "iTunesStoreIdentifier", "iTunes Store identifier for Content")
+    def itunes_store_identifier(self) -> Optional[int]:
+        """Itunes Store identifier."""
+        return self._itunes_store_identifier
+
 
 class App:
     """Information about an app."""

pyatv/protocols/mrp/__init__.py

@@ -142,6 +142,7 @@
     FeatureName.SeasonNumber: "seasonNumber",
     FeatureName.EpisodeNumber: "episodeNumber",
     FeatureName.ContentIdentifier: "contentIdentifier",
+    FeatureName.iTunesStoreIdentifier: "iTunesStoreIdentifier",
 }
 
 DELAY_BETWEEN_COMMANDS = 0.1
@@ -267,6 +268,10 @@ def content_identifier() -> str:
         """Content identifier."""
         return state.metadata_field("contentIdentifier")
 
+    def itunes_store_identifier() -> int:
+        """Itunes Store identifier."""
+        return state.metadata_field("iTunesStoreIdentifier")
+
     return Playing(
         media_type=media_type(),
         device_state=device_state(),
@@ -283,6 +288,7 @@ def content_identifier() -> str:
         season_number=season_number(),
         episode_number=episode_number(),
         content_identifier=content_identifier(),
+        itunes_store_identifier=itunes_store_identifier(),
     )
 
 

tests/fake_device/mrp.py

@@ -118,6 +118,8 @@ def _fill_item(item, metadata):
         md.episodeNumber = metadata.episode_number
     if metadata.content_identifier:
         md.contentIdentifier = metadata.content_identifier
+    if metadata.itunes_store_identifier:
+        md.iTunesStoreIdentifier = metadata.itunes_store_identifier
 
 
 def _set_state_message(metadata, identifier):
@@ -194,6 +196,7 @@ def __init__(self, **kwargs):
         self.skip_time = kwargs.get("skip_time")
         self.app_name = kwargs.get("app_name")
         self.content_identifier = kwargs.get("content_identifier")
+        self.itunes_store_identifier = kwargs.get("itunes_store_identifier")
 
 
 class FakeMrpState:

tests/protocols/mrp/test_mrp_functional.py

@@ -542,6 +542,7 @@ async def test_metadata_tv_playing(self):
             season_number=12,
             episode_number=4,
             content_identifier="identifier",
+            itunes_store_identifier=123456789,
         )
 
         with faketime("pyatv", 0):
@@ -554,6 +555,7 @@ async def test_metadata_tv_playing(self):
             self.assertEqual(playing.season_number, 12)
             self.assertEqual(playing.episode_number, 4)
             self.assertEqual(playing.content_identifier, "identifier")
+            self.assertEqual(playing.itunes_store_identifier, 123456789)
 
         self.assertFeatures(
             FeatureState.Available,

tests/scripts/test_atvscript.py

@@ -103,6 +103,7 @@ async def test_mrp_idle(scriptenv):
             "season_number": None,
             "episode_number": None,
             "content_identifier": None,
+            "itunes_store_identifier": None,
         },
     )
     assert exit_code == 0

tests/test_interface.py

@@ -128,6 +128,7 @@ def test_playing_basic_fields():
             season_number=1245,
             episode_number=2468,
             content_identifier="content_id",
+            itunes_store_identifier=123456789,
         )
     )
     assert "mytitle" in out
@@ -138,6 +139,7 @@ def test_playing_basic_fields():
     assert "1245" in out
     assert "2468" in out
     assert "content_id" in out
+    assert "123456789" in out
 
 
 @pytest.mark.parametrize(
@@ -197,7 +199,7 @@ def test_playing_custom_hash():
 def test_playing_eq_ensure_member_count():
     # Fail if a property is added or removed to interface, just as a reminder to
     # update equality comparison
-    assert len(Playing().__dict__) == 15
+    assert len(Playing().__dict__) == 16
 
 
 @pytest.mark.parametrize(