Merge pull request #19 from dianakhuang/invert-rule

Adding inversion operator and a test to verify that it works.

bridgekeeper/rule_attribute_tests.py

@@ -49,3 +49,15 @@ def test_when_called_without_object():
     user = UserFactory(username='a')
     p = Attribute('name', lambda u: u.username)
     assert not p.check(user)
+
+
+@pytest.mark.django_db
+def test_inversion_of_attribute():
+    u1 = UserFactory(username='a')
+    u2 = UserFactory(username='b')
+    s1 = StoreFactory(name='a')
+    s2 = StoreFactory(name='b')
+    p = ~Attribute('name', lambda u: u.username)
+
+    assert p.check(u1, s2)
+    assert p.check(u2, s1)

bridgekeeper/rules.py

@@ -131,6 +131,9 @@ def __or__(self, other):
     def __not__(self):
         return Not(self)
 
+    def __invert__(self):
+        return Not(self)
+
 
 class BinaryCompositeRule(Rule):
     def __init__(self, left, right):
@@ -220,6 +223,9 @@ def query(self, user):
     def check(self, user, instance=None):
         return not self.base.check(user, instance)
 
+    def __invert__(self):
+        return self.base
+
 
 class blanket_rule(Rule):  # noqa: used as a decorator, so should be lowercase
     """A decorator for rules that don't depend on objects.