Merge pull request #195 from sturmianseq/fix

Removing state pollution in `parser_cache`

test/test_cache.py

@@ -185,6 +185,9 @@ def test_permission_error(monkeypatch):
     was_called = False
 
     monkeypatch.setattr(cache, '_save_to_file_system', save)
+    try:
         with pytest.warns(Warning):
             parse(path=__file__, cache=True, diff_cache=True)
         assert was_called
+    finally:
+        parser_cache.clear()