meta: cache: fix caching and add tests (MR 2252)

Just use inspect... Fix some fairly big issues and add some tests

Signed-off-by: Caleb Connolly <caleb@postmarketos.org>

pmb/meta/test_cache.py

@@ -0,0 +1,90 @@
+from typing import List
+import pytest
+
+from . import Cache, Wrapper
+
+
+def test_cache_hits_basic():
+    def multiply_2(x: int) -> int:
+        return x * 2
+    
+    multiply_2_cached = Cache("x")(multiply_2)
+    
+    assert isinstance(multiply_2_cached, Wrapper)
+
+    assert multiply_2(2) == 4
+
+    assert multiply_2_cached(2) == 4
+    assert multiply_2_cached.misses == 1
+
+    assert multiply_2_cached(2) == 4
+    assert multiply_2_cached.hits == 1
+
+    assert multiply_2_cached(3) == 6
+    assert multiply_2_cached.misses == 2
+
+    assert multiply_2_cached(4) == 8
+    assert multiply_2_cached.misses == 3
+
+    assert multiply_2_cached(3) == 6
+    assert multiply_2_cached.hits == 2
+
+def test_cache_hits_kwargs():
+    def multiply_2(x: int, y: int = 2, z: List[int] = []) -> int:
+        return x * y + sum(z)
+
+    multiply_2_cached = Cache("x", "y", "z")(multiply_2)
+
+    assert isinstance(multiply_2_cached, Wrapper)
+
+    assert multiply_2(2) == 4
+    assert multiply_2_cached(2) == 4
+    assert multiply_2_cached.misses == 1
+    assert multiply_2(2, 3) == multiply_2_cached(2, 3)
+    assert multiply_2_cached.misses == 2
+    assert multiply_2(2, 3) == multiply_2_cached(2, 3)
+    assert multiply_2_cached.hits == 1
+
+    assert multiply_2(3, 4, [1, 1]) == 14
+    assert multiply_2_cached(3, 4, [1, 1]) == 14
+    assert multiply_2_cached(3, 3, [1, 1]) == 11
+    assert multiply_2_cached.misses == 4
+    assert multiply_2_cached(3, 4, [1, 1]) == 14
+    assert multiply_2_cached.hits == 2
+
+    # Should only cache when y=3
+    multiply_2_cached_y3 = Cache("x", "z", y=3)(multiply_2)
+
+    assert multiply_2_cached_y3(1, 1, [1, 1]) == 3
+    assert multiply_2_cached_y3.misses == 1
+    
+    assert multiply_2_cached_y3(1, 1, [1, 1]) == 3
+    assert multiply_2_cached_y3.misses == 2
+
+    assert multiply_2_cached_y3(1, 3, [4, 1]) == 8
+    assert multiply_2_cached_y3.misses == 3
+    assert multiply_2_cached_y3(1, 3, [4, 1]) == 8
+    assert multiply_2_cached_y3.hits == 1
+
+def test_build_key():
+    def multiply_2(x: int, y: int = 2, z: List[int] = []) -> int:
+        return x * y + sum(z)
+
+    multiply_2_cached = Cache("x", "y", "z")(multiply_2)
+
+    key = multiply_2_cached.cache.build_key(multiply_2, 1, 2, [3, 4])
+    print(f"KEY: {key}")
+
+    assert key == "~1~2~[3, 4]~"
+
+    multiply_2_cached_y4 = Cache("x", "z", y=4)(multiply_2)
+
+    # Key should be None since y != 4
+    key = multiply_2_cached_y4.cache.build_key(multiply_2, 1, 2, [3, 4])
+    print(f"Expecting None KEY: {key}")
+    assert key is None
+
+    # Now we expect a real key since y is 4
+    key = multiply_2_cached_y4.cache.build_key(multiply_2, 1, 4, [3, 4])
+    print(f"KEY: {key}")
+    assert key == "~y=(4)~1~[3, 4]~"