added some more tests

tests/test_cache.py

@@ -1,5 +1,7 @@
 from __future__ import unicode_literals
 
+import pytest
+
 from textual._cache import LRUCache
 
 
@@ -57,3 +59,70 @@ def test_lru_cache_get():
     # Check it kicked out the 'oldest' key
     assert "egg" not in cache
     assert "eggegg" in cache
+
+
+def test_lru_cache_mapping():
+    """Test cache values can be set and read back."""
+    cache = LRUCache(3)
+    cache["foo"] = 1
+    cache.set("bar", 2)
+    cache.set("baz", 3)
+    assert cache["foo"] == 1
+    assert cache["bar"] == 2
+    assert cache.get("baz") == 3
+
+
+def test_lru_cache_clear():
+    cache = LRUCache(3)
+    assert len(cache) == 0
+    cache["foo"] = 1
+    assert "foo" in cache
+    assert len(cache) == 1
+    cache.clear()
+    assert "foo" not in cache
+    assert len(cache) == 0
+
+
+def test_lru_cache_bool():
+    cache = LRUCache(3)
+    assert not cache
+    cache["foo"] = "bar"
+    assert cache
+
+
+@pytest.mark.parametrize(
+    "keys,expected",
+    [
+        ((), ()),
+        (("foo",), ("foo",)),
+        (("foo", "bar"), ("foo", "bar")),
+        (("foo", "bar", "baz"), ("foo", "bar", "baz")),
+        (("foo", "bar", "baz", "egg"), ("bar", "baz", "egg")),
+        (("foo", "bar", "baz", "egg", "bob"), ("baz", "egg", "bob")),
+    ],
+)
+def test_lru_cache_evicts(keys: list[str], expected: list[str]):
+    """Test adding adding additional values evicts oldest key"""
+    cache = LRUCache(3)
+    for value, key in enumerate(keys):
+        cache[key] = value
+    assert tuple(cache.keys()) == expected
+
+
+@pytest.mark.parametrize(
+    "keys,expected_len",
+    [
+        ((), 0),
+        (("foo",), 1),
+        (("foo", "bar"), 2),
+        (("foo", "bar", "baz"), 3),
+        (("foo", "bar", "baz", "egg"), 3),
+        (("foo", "bar", "baz", "egg", "bob"), 3),
+    ],
+)
+def test_lru_cache_len(keys: list[str], expected_len: int):
+    """Test adding adding additional values evicts oldest key"""
+    cache = LRUCache(3)
+    for value, key in enumerate(keys):
+        cache[key] = value
+    assert len(cache) == expected_len