fix tests

tests/test_cache.py

@@ -0,0 +1,59 @@
+from __future__ import unicode_literals
+
+from textual._cache import LRUCache
+
+
+def test_lru_cache():
+    cache = LRUCache(3)
+
+    # insert some values
+    cache["foo"] = 1
+    cache["bar"] = 2
+    cache["baz"] = 3
+    assert "foo" in cache
+    assert "bar" in cache
+    assert "baz" in cache
+
+    #  Cache size is 3, so the following should kick oldest one out
+    cache["egg"] = 4
+    assert "foo" not in cache
+    assert "egg" in cache
+
+    # cache is now full
+    # look up two keys
+    cache["bar"]
+    cache["baz"]
+
+    # Insert a new value
+    cache["eggegg"] = 5
+    assert len(cache) == 3
+    # Check it kicked out the 'oldest' key
+    assert "egg" not in cache
+    assert "eggegg" in cache
+
+
+def test_lru_cache_get():
+    cache = LRUCache(3)
+
+    # insert some values
+    cache["foo"] = 1
+    cache["bar"] = 2
+    cache["baz"] = 3
+    assert "foo" in cache
+
+    #  Cache size is 3, so the following should kick oldest one out
+    cache["egg"] = 4
+    # assert len(cache) == 3
+    assert cache.get("foo") is None
+    assert "egg" in cache
+
+    # cache is now full
+    # look up two keys
+    cache.get("bar")
+    cache.get("baz")
+
+    # Insert a new value
+    cache["eggegg"] = 5
+    # Check it kicked out the 'oldest' key
+    assert "egg" not in cache
+    assert "eggegg" in cache