def test_delete():
test_obj = PersistentLRUCache(directory=directory)
test_obj.write("some_key", "42")
test_obj.write("42", "some_key")
test_obj.delete("some_key")
test_obj.delete("non_existant_key")
test_obj.delete("42")
assert_raises( KeyError, test_obj.get_value, ("42") )
assert_raises( KeyError, test_obj.get_value, ("some_key") )
assert not test_obj.exists("42")
assert not test_obj.exists("some_key")
def test_exists():
test_obj = PersistentLRUCache(directory=directory)
assert not test_obj.exists("some_key")
test_obj.write("some_key", "42")
assert test_obj.exists("some_key")
assert not test_obj.exists("some_other_key")