Test the grouping-by-key feature of the LatestValueCache

Signed-off-by: Sahas Subramanian <[email protected]>

Author: shsms

tests/test_latest_value_cache_integration.py

@@ -43,3 +43,52 @@ async def test_latest_value_cache() -> None:
     await asyncio.sleep(0)
 
     assert cache.get() == 19
+
+
+@pytest.mark.integration
+async def test_latest_value_cache_key() -> None:
+    """Ensure LatestValueCache works with keys."""
+    channel = Broadcast[tuple[int, str]](name="lvc_test")
+
+    cache = LatestValueCache(channel.new_receiver(), key=lambda x: x[0])
+    sender = channel.new_sender()
+
+    assert not cache.has_value()
+    with pytest.raises(ValueError, match="No value has been received yet."):
+        cache.get()
+    with pytest.raises(ValueError, match="No value received for key: 0"):
+        cache.get(0)
+
+    await sender.send((5, "a"))
+    await sender.send((6, "b"))
+    await sender.send((5, "c"))
+    await asyncio.sleep(0)
+
+    assert cache.has_value()
+    assert cache.has_value(5)
+    assert cache.has_value(6)
+    assert not cache.has_value(7)
+
+    assert cache.get() == (5, "c")
+    assert cache.get(5) == (5, "c")
+    assert cache.get(6) == (6, "b")
+
+    with pytest.raises(ValueError, match="No value received for key: 7"):
+        cache.get(7)
+
+    await sender.send((12, "d"))
+    await asyncio.sleep(0)
+
+    assert cache.get() == (12, "d")
+    assert cache.get() == (12, "d")
+    assert cache.get(12) == (12, "d")
+    assert cache.get(12) == (12, "d")
+    assert cache.get(5) == (5, "c")
+    assert cache.get(6) == (6, "b")
+
+    await sender.send((6, "e"))
+    await sender.send((6, "f"))
+    await sender.send((6, "g"))
+    await asyncio.sleep(0)
+
+    assert cache.get(6) == (6, "g")