Add unit tests for resource cache

tiled/_tests/test_resource_cache.py

@@ -0,0 +1,45 @@
+import cachetools
+
+from ..adapters.resource_cache import default_resource_cache, with_resource_cache
+
+
+def test_simple_cache():
+    counter = 0
+
+    def f():
+        nonlocal counter
+        counter += 1
+        return "some value"
+
+    cache = cachetools.Cache(maxsize=1)
+    with_resource_cache("test_key", f, _resource_cache=cache)
+    with_resource_cache("test_key", f, _resource_cache=cache)
+    assert counter == 1
+
+
+def test_default_cache():
+    counter = 0
+
+    def f():
+        nonlocal counter
+        counter += 1
+        return "some value"
+
+    cache = default_resource_cache()
+    with_resource_cache("test_key", f, _resource_cache=cache)
+    with_resource_cache("test_key", f, _resource_cache=cache)
+    assert counter == 1
+
+
+def test_cache_zero_size():
+    counter = 0
+
+    def f():
+        nonlocal counter
+        counter += 1
+        return "some value"
+
+    cache = cachetools.Cache(maxsize=0)
+    with_resource_cache("test_key", f, _resource_cache=cache)
+    with_resource_cache("test_key", f, _resource_cache=cache)
+    assert counter == 2