Copy async_lru for Python 3.7 compatibility

tests/external/test_size.py

@@ -0,0 +1,58 @@
+import asyncio
+
+import pytest
+from great_ai.external.async_lru import _make_key, alru_cache
+
+pytestmark = pytest.mark.asyncio
+
+
+async def test_alru_cache_removing_lru_keys(check_lru, loop):
+    @alru_cache(maxsize=3)
+    async def coro(val):
+        return val
+
+    key5 = _make_key((5,), {}, False)
+    key4 = _make_key((4,), {}, False)
+    key3 = _make_key((3,), {}, False)
+    key2 = _make_key((2,), {}, False)
+    key1 = _make_key((1,), {}, False)
+
+    for i, v in enumerate([3, 4, 5]):
+        await coro(v)
+        check_lru(coro, hits=0, misses=i + 1, cache=i + 1, tasks=0, maxsize=3)
+
+    check_lru(coro, hits=0, misses=3, cache=3, tasks=0, maxsize=3)
+    assert list(coro._cache) == [key3, key4, key5]
+
+    for v in [3, 2, 1]:
+        await coro(v)
+    check_lru(coro, hits=1, misses=5, cache=3, tasks=0, maxsize=3)
+    assert list(coro._cache) == [key3, key2, key1]
+
+
+async def test_alru_cache_none_max_size(check_lru, loop):
+    @alru_cache(maxsize=None)
+    async def coro(val):
+        return val
+
+    inputs = [1, 2, 3, 4] * 2
+    coros = [coro(v) for v in inputs]
+
+    ret = await asyncio.gather(*coros)
+
+    check_lru(coro, hits=4, misses=4, cache=4, tasks=0, maxsize=None)
+    assert ret == inputs
+
+
+async def test_alru_cache_zero_max_size(check_lru, loop):
+    @alru_cache(maxsize=0)
+    async def coro(val):
+        return val
+
+    inputs = [1, 2, 3, 4] * 2
+    coros = [coro(v) for v in inputs]
+
+    ret = await asyncio.gather(*coros)
+
+    check_lru(coro, hits=0, misses=8, cache=0, tasks=0, maxsize=0)
+    assert ret == inputs