Merge pull request #1424 from alex/verify-interfaces

Fixes #1024 -- a utility function for checking an implementor against an ABC

1 files changed, 63 insertions, 0 deletions

diff --git a/tests/test_interfaces.py b/tests/test_interfaces.py
new file mode 100644
index 00000000..b988abee
--- /dev/null
+++ b/tests/test_interfaces.py
@@ -0,0 +1,63 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import abc
+
+import pytest
+
+import six
+
+from cryptography.utils import InterfaceNotImplemented, verify_interface
+
+
+class TestVerifyInterface(object):
+    def test_verify_missing_method(self):
+        @six.add_metaclass(abc.ABCMeta)
+        class SimpleInterface(object):
+            @abc.abstractmethod
+            def method(self):
+                """A simple method"""
+
+        class NonImplementer(object):
+            pass
+
+        with pytest.raises(InterfaceNotImplemented):
+            verify_interface(SimpleInterface, NonImplementer)
+
+    def test_different_arguments(self):
+        @six.add_metaclass(abc.ABCMeta)
+        class SimpleInterface(object):
+            @abc.abstractmethod
+            def method(self, a):
+                """Method with one argument"""
+
+        class NonImplementer(object):
+            def method(self):
+                """Method with no arguments"""
+
+        with pytest.raises(InterfaceNotImplemented):
+            verify_interface(SimpleInterface, NonImplementer)
+
+    def test_handles_abstract_property(self):
+        @six.add_metaclass(abc.ABCMeta)
+        class SimpleInterface(object):
+            @abc.abstractproperty
+            def property(self):
+                """An abstract property"""
+
+        class NonImplementer(object):
+            @property
+            def property(self):
+                """A concrete property"""
+
+        verify_interface(SimpleInterface, NonImplementer)