moar tests

src/textual/_cache.py

@@ -14,7 +14,7 @@ where the overhead of the cache is a small fraction of the total processing time
 
 from __future__ import annotations
 
-from typing import Dict, Generic, KeysView, TypeVar, overload
+from typing import cast, Dict, Generic, KeysView, TypeVar, overload
 
 CacheKey = TypeVar("CacheKey")
 CacheValue = TypeVar("CacheValue")
@@ -257,16 +257,24 @@ class FIFOCache(Generic[CacheKey, CacheValue]):
         Returns:
             Union[CacheValue, Optional[DefaultValue]]: Either the value or a default.
         """
-        return self._cache.get(key, default)
+        try:
+            result = self._cache[key]
+        except KeyError:
+            self.misses += 1
+            return default
+        else:
+            self.hits += 1
+            return result
 
     def __getitem__(self, key: CacheKey) -> CacheValue:
         try:
-            return self._cache[key]
+            result = self._cache[key]
         except KeyError:
             self.misses += 1
             raise KeyError(key) from None
-        finally:
+        else:
             self.hits += 1
+            return result
 
-    def __container__(self, key: CacheKey) -> bool:
+    def __contains__(self, key: CacheKey) -> bool:
         return key in self._cache

tests/test_cache.py

@@ -152,7 +152,9 @@ def test_lru_cache_len(keys: list[str], expected_len: int):
 def test_fifo_cache():
     cache = FIFOCache(4)
     assert not cache
+    assert "foo" not in cache
     cache["foo"] = 1
+    assert "foo" in cache
     assert cache
     cache["bar"] = 2
     cache["baz"] = 3
@@ -171,3 +173,35 @@ def test_fifo_cache():
     cache.clear()
     assert len(cache) == 0
     assert list(cache.keys()) == []
+
+
+def test_fifo_cache_hits():
+    cache = FIFOCache(4)
+    assert cache.hits == 0
+    assert cache.misses == 0
+
+    try:
+        cache["foo"]
+    except KeyError:
+        assert cache.hits == 0
+        assert cache.misses == 1
+
+    cache["foo"] = 1
+    assert cache.hits == 0
+    assert cache.misses == 1
+
+    cache["foo"]
+    cache["foo"]
+
+    assert cache.hits == 2
+    assert cache.misses == 1
+
+    cache.get("bar")
+    assert cache.hits == 2
+    assert cache.misses == 2
+
+    cache.get("foo")
+    assert cache.hits == 3
+    assert cache.misses == 2
+
+    assert str(cache) == "<FIFOCache maxsize=4 hits=3 misses=2>"