Test classmethod (#512)

setup.cfg

@@ -78,7 +78,7 @@ testpaths = tests/
 junit_family=xunit2
 asyncio_mode=auto
 timeout=15
-
+xfail_strict = true
 
 [mypy]
 strict=True

tests/test_basic.py

@@ -1,4 +1,6 @@
 import asyncio
+import platform
+import sys
 from functools import _CacheInfo, partial
 from typing import Callable
 
@@ -188,6 +190,28 @@ async def coro(self) -> int:
     )
 
 
+@pytest.mark.xfail(
+    sys.version_info[:2] == (3, 9) and platform.python_implementation() != "PyPy",
+    reason="#511",
+)
+async def test_alru_cache_classmethod() -> None:
+    class A:
+        offset = 3
+
+        @classmethod
+        @alru_cache
+        async def coro(cls, val: int) -> int:
+            return val + cls.offset
+
+    assert await A.coro(5) == 8
+    assert A.coro.cache_parameters() == _CacheParameters(
+        typed=False,
+        maxsize=128,
+        tasks=0,
+        closed=False,
+    )
+
+
 async def test_invalidate_cache_for_method() -> None:
     class A:
         @alru_cache