When using a test double for backends, always use one which really implements the interface

3 files changed, 16 insertions, 30 deletions

diff --git a/tests/hazmat/primitives/test_cmac.py b/tests/hazmat/primitives/test_cmac.py
index 49e2043e..c778ebee 100644
--- a/tests/hazmat/primitives/test_cmac.py
+++ b/tests/hazmat/primitives/test_cmac.py
@@ -21,7 +21,6 @@ import pytest
 
 import six
 
-from cryptography import utils
 from cryptography.exceptions import (
     AlreadyFinalized, InvalidSignature, _Reasons
 )
@@ -31,7 +30,8 @@ from cryptography.hazmat.primitives.ciphers.algorithms import (
 )
 from cryptography.hazmat.primitives.cmac import CMAC
 
-from tests.utils import (
+from ..backends.test_multibackend import DummyCMACBackend
+from ...utils import (
     load_nist_vectors, load_vectors_from_file, raises_unsupported_algorithm
 )
 
@@ -195,18 +195,14 @@ class TestCMAC(object):
 
 
 def test_copy():
-    @utils.register_interface(CMACBackend)
-    class PretendBackend(object):
-        pass
-
-    pretend_backend = PretendBackend()
+    backend = DummyCMACBackend([AES])
     copied_ctx = pretend.stub()
     pretend_ctx = pretend.stub(copy=lambda: copied_ctx)
     key = b"2b7e151628aed2a6abf7158809cf4f3c"
-    cmac = CMAC(AES(key), backend=pretend_backend, ctx=pretend_ctx)
+    cmac = CMAC(AES(key), backend=backend, ctx=pretend_ctx)
 
-    assert cmac._backend is pretend_backend
-    assert cmac.copy()._backend is pretend_backend
+    assert cmac._backend is backend
+    assert cmac.copy()._backend is backend
 
 
 def test_invalid_backend():
diff --git a/tests/hazmat/primitives/test_hashes.py b/tests/hazmat/primitives/test_hashes.py
index 0fdd7550..053a1a46 100644
--- a/tests/hazmat/primitives/test_hashes.py
+++ b/tests/hazmat/primitives/test_hashes.py
@@ -20,13 +20,12 @@ import pytest
 import six
 
 from cryptography import utils
-from cryptography.exceptions import (
-    AlreadyFinalized, _Reasons
-)
+from cryptography.exceptions import AlreadyFinalized, _Reasons
 from cryptography.hazmat.backends.interfaces import HashBackend
 from cryptography.hazmat.primitives import hashes, interfaces
 
 from .utils import generate_base_hash_test
+from ..backends.test_multibackend import DummyHashBackend
 from ...utils import raises_unsupported_algorithm
 
 
@@ -45,16 +44,11 @@ class TestHashContext(object):
             m.update(six.u("\u00FC"))
 
     def test_copy_backend_object(self):
-        @utils.register_interface(HashBackend)
-        class PretendBackend(object):
-            pass
-
-        pretend_backend = PretendBackend()
+        backend = DummyHashBackend([hashes.SHA1])
         copied_ctx = pretend.stub()
         pretend_ctx = pretend.stub(copy=lambda: copied_ctx)
-        h = hashes.Hash(hashes.SHA1(), backend=pretend_backend,
-                        ctx=pretend_ctx)
-        assert h._backend is pretend_backend
+        h = hashes.Hash(hashes.SHA1(), backend=backend, ctx=pretend_ctx)
+        assert h._backend is backend
         assert h.copy()._backend is h._backend
 
     def test_hash_algorithm_instance(self, backend):
diff --git a/tests/hazmat/primitives/test_hmac.py b/tests/hazmat/primitives/test_hmac.py
index 3553632c..497b37e1 100644
--- a/tests/hazmat/primitives/test_hmac.py
+++ b/tests/hazmat/primitives/test_hmac.py
@@ -27,6 +27,7 @@ from cryptography.hazmat.backends.interfaces import HMACBackend
 from cryptography.hazmat.primitives import hashes, hmac, interfaces
 
 from .utils import generate_base_hmac_test
+from ..backends.test_multibackend import DummyHMACBackend
 from ...utils import raises_unsupported_algorithm
 
 
@@ -56,17 +57,12 @@ class TestHMAC(object):
             h.update(six.u("\u00FC"))
 
     def test_copy_backend_object(self):
-        @utils.register_interface(HMACBackend)
-        class PretendBackend(object):
-            pass
-
-        pretend_backend = PretendBackend()
+        backend = DummyHMACBackend([hashes.SHA1])
         copied_ctx = pretend.stub()
         pretend_ctx = pretend.stub(copy=lambda: copied_ctx)
-        h = hmac.HMAC(b"key", hashes.SHA1(), backend=pretend_backend,
-                      ctx=pretend_ctx)
-        assert h._backend is pretend_backend
-        assert h.copy()._backend is pretend_backend
+        h = hmac.HMAC(b"key", hashes.SHA1(), backend=backend, ctx=pretend_ctx)
+        assert h._backend is backend
+        assert h.copy()._backend is backend
 
     def test_hmac_algorithm_instance(self, backend):
         with pytest.raises(TypeError):