add tests for caching

custodian/tests/test_utils.py

@@ -0,0 +1,38 @@
+import unittest
+
+from custodian.utils import tracked_lru_cache
+
+
+class TrackedLruCacheTest(unittest.TestCase):
+    def setUp(self):
+        # clear cache before and after each test to avoid
+        # unexpected caching from other tests
+        tracked_lru_cache.cache_clear()
+
+    def test_cache_and_clear(self):
+        n_calls = 0
+
+        @tracked_lru_cache
+        def some_func(x):
+            nonlocal n_calls
+            n_calls += 1
+            return x
+
+        assert some_func(1) == 1
+        assert n_calls == 1
+        assert some_func(2) == 2
+        assert n_calls == 2
+        assert some_func(1) == 1
+        assert n_calls == 2
+
+        assert len(tracked_lru_cache.cached_functions) == 1
+
+        tracked_lru_cache.cache_clear()
+
+        assert len(tracked_lru_cache.cached_functions) == 0
+
+        assert some_func(1) == 1
+        assert n_calls == 3
+
+    def tearDown(self):
+        tracked_lru_cache.cache_clear()

custodian/utils.py

@@ -70,6 +70,10 @@ def __init__(self, func):
         self.func = functools.lru_cache(func)
         functools.update_wrapper(self, func)
 
+        # expose standard lru_cache functions
+        self.cache_info = self.func.cache_info
+        self.cache_clear = self.func.cache_clear
+
     def __call__(self, *args, **kwargs):
         """
         Call the decorated function

custodian/vasp/tests/test_io.py

@@ -0,0 +1,27 @@
+import os
+import unittest
+
+from custodian.utils import tracked_lru_cache
+from custodian.vasp.io import load_outcar, load_vasprun
+
+test_dir = os.path.join(os.path.dirname(__file__), "..", "..", "..", "test_files")
+
+
+class IOTest(unittest.TestCase):
+    def test_load_outcar(self):
+        outcar = load_outcar(os.path.join(test_dir, "large_sigma", "OUTCAR"))
+        assert outcar is not None
+        outcar2 = load_outcar(os.path.join(test_dir, "large_sigma", "OUTCAR"))
+
+        assert outcar is outcar2
+
+        assert len(tracked_lru_cache.cached_functions) == 1
+
+    def test_load_vasprun(self):
+        vr = load_vasprun(os.path.join(test_dir, "large_sigma", "vasprun.xml"))
+        assert vr is not None
+        vr2 = load_vasprun(os.path.join(test_dir, "large_sigma", "vasprun.xml"))
+
+        assert vr is vr2
+
+        assert len(tracked_lru_cache.cached_functions) == 1