8 files changed, 89 insertions, 1 deletions
diff --git a/tests/hazmat/backends/test_commoncrypto.py b/tests/hazmat/backends/test_commoncrypto.py
index 28d1a6ca..b79c02e0 100644
--- a/tests/hazmat/backends/test_commoncrypto.py
+++ b/tests/hazmat/backends/test_commoncrypto.py
@@ -30,6 +30,7 @@ from ...utils import raises_unsupported_algorithm
 class DummyCipher(object):
     name = "dummy-cipher"
     block_size = 128
+    key_size = 128
 
 
 @pytest.mark.skipif("commoncrypto" not in
diff --git a/tests/hazmat/backends/test_openssl.py b/tests/hazmat/backends/test_openssl.py
index 39708f82..65113f1a 100644
--- a/tests/hazmat/backends/test_openssl.py
+++ b/tests/hazmat/backends/test_openssl.py
@@ -52,6 +52,7 @@ class DummyMode(object):
 @utils.register_interface(interfaces.CipherAlgorithm)
 class DummyCipher(object):
     name = "dummy-cipher"
+    key_size = 128
 
 
 @utils.register_interface(interfaces.AsymmetricPadding)
@@ -62,6 +63,8 @@ class DummyPadding(object):
 @utils.register_interface(interfaces.HashAlgorithm)
 class DummyHash(object):
     name = "dummy-hash"
+    block_size = 128
+    digest_size = 128
 
 
 class DummyMGF(object):
diff --git a/tests/hazmat/primitives/test_block.py b/tests/hazmat/primitives/test_block.py
index 6ee230a7..53b87341 100644
--- a/tests/hazmat/primitives/test_block.py
+++ b/tests/hazmat/primitives/test_block.py
@@ -44,6 +44,7 @@ class DummyMode(object):
 @utils.register_interface(interfaces.CipherAlgorithm)
 class DummyCipher(object):
     name = "dummy-cipher"
+    key_size = 128
 
 
 @pytest.mark.requires_backend_interface(interface=CipherBackend)
diff --git a/tests/hazmat/primitives/test_ec.py b/tests/hazmat/primitives/test_ec.py
index decb3716..683df046 100644
--- a/tests/hazmat/primitives/test_ec.py
+++ b/tests/hazmat/primitives/test_ec.py
@@ -68,11 +68,20 @@ class DummyCurve(object):
 
 @utils.register_interface(interfaces.EllipticCurveSignatureAlgorithm)
 class DummySignatureAlgorithm(object):
-    pass
+    algorithm = None
 
 
 @utils.register_interface(EllipticCurveBackend)
 class DeprecatedDummyECBackend(object):
+    def _unimplemented(self):
+        raise NotImplementedError
+
+    elliptic_curve_signature_algorithm_supported = _unimplemented
+    load_elliptic_curve_private_numbers = _unimplemented
+    load_elliptic_curve_public_numbers = _unimplemented
+    elliptic_curve_supported = _unimplemented
+    generate_elliptic_curve_private_key = _unimplemented
+
     def elliptic_curve_private_key_from_numbers(self, numbers):
         return b"private_key"
 
diff --git a/tests/hazmat/primitives/test_hashes.py b/tests/hazmat/primitives/test_hashes.py
index ba4f53af..79fc25c3 100644
--- a/tests/hazmat/primitives/test_hashes.py
+++ b/tests/hazmat/primitives/test_hashes.py
@@ -33,6 +33,8 @@ from ...utils import raises_unsupported_algorithm
 @utils.register_interface(interfaces.HashAlgorithm)
 class UnsupportedDummyHash(object):
     name = "unsupported-dummy-hash"
+    block_size = 128
+    digest_size = 128
 
 
 @pytest.mark.requires_backend_interface(interface=HashBackend)
diff --git a/tests/hazmat/primitives/test_hmac.py b/tests/hazmat/primitives/test_hmac.py
index baf8a299..01b1cdcb 100644
--- a/tests/hazmat/primitives/test_hmac.py
+++ b/tests/hazmat/primitives/test_hmac.py
@@ -33,6 +33,8 @@ from ...utils import raises_unsupported_algorithm
 @utils.register_interface(interfaces.HashAlgorithm)
 class UnsupportedDummyHash(object):
     name = "unsupported-dummy-hash"
+    block_size = 128
+    digest_size = 128
 
 
 @pytest.mark.supported(
diff --git a/tests/hazmat/primitives/test_pbkdf2hmac.py b/tests/hazmat/primitives/test_pbkdf2hmac.py
index e928fc6a..fa925877 100644
--- a/tests/hazmat/primitives/test_pbkdf2hmac.py
+++ b/tests/hazmat/primitives/test_pbkdf2hmac.py
@@ -31,6 +31,8 @@ from ...utils import raises_unsupported_algorithm
 @utils.register_interface(interfaces.HashAlgorithm)
 class DummyHash(object):
     name = "dummy-hash"
+    block_size = 128
+    digest_size = 128
 
 
 class TestPBKDF2HMAC(object):
diff --git a/tests/test_interfaces.py b/tests/test_interfaces.py
new file mode 100644
index 00000000..0c72ad33
--- /dev/null
+++ b/tests/test_interfaces.py
@@ -0,0 +1,68 @@
+# 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, register_interface, 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"""
+
+        @register_interface(SimpleInterface)
+        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"""
+
+        @register_interface(SimpleInterface)
+        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"""
+
+        @register_interface(SimpleInterface)
+        class NonImplementer(object):
+            @property
+            def property(self):
+                """A concrete property"""
+
+        verify_interface(SimpleInterface, NonImplementer)