Take into account restriction's strict value

So far Nailgun always assumes that restrictions are strict, and doesn't
care about explicit (specified in restriction) `strict` value. This
commit fixes that, and if some restriction has an explicit `strict`
option it will be taken into account.

Change-Id: I5ef0e91f42cd708be5df56da461af4d7b568ae42
Closes-Bug: #1587773

nailgun/nailgun/test/unit/test_attributes_validator.py

@@ -491,3 +491,29 @@ class TestBasicAttributesValidator(base_test.BaseTestCase):
             errors.InvalidData,
             base.BasicAttributesValidator.validate_attributes,
             attrs)
+
+    def test_restriction_strict(self):
+        context = {'context': {'existing': {'value': 13}}}
+
+        for strict in (False, True):
+            attrs = {
+                'section': {
+                    'subsection': {
+                        'restrictions': [{
+                            'condition': 'context:nonexisting.value == 42',
+                            'strict': strict,
+                        }],
+                    },
+                },
+            }
+
+            if strict:
+                assert_fn = self.assertRaises
+            else:
+                assert_fn = self.assertNotRaises
+
+            assert_fn(
+                TypeError,
+                base.BasicAttributesValidator.validate_attributes,
+                attrs,
+                models=context)

nailgun/nailgun/utils/restrictions.py

@@ -194,7 +194,9 @@ class RestrictionBase(object):
             # Filter which restriction satisfied condition
             satisfied = filter(
                 lambda item: Expression(
-                    item.get('condition'), models, strict=strict).evaluate(),
+                    item.get('condition'),
+                    models,
+                    strict=item.get('strict', strict)).evaluate(),
                 filterd_by_action_restrictions)
 
         return {