4 files changed, 66 insertions, 7 deletions
diff --git a/tests/hazmat/primitives/test_ciphers.py b/tests/hazmat/primitives/test_ciphers.py
index d9f83535..bd9625e9 100644
--- a/tests/hazmat/primitives/test_ciphers.py
+++ b/tests/hazmat/primitives/test_ciphers.py
@@ -17,9 +17,12 @@ import binascii
 
 import pytest
 
+from cryptography.exceptions import UnsupportedInterface
+from cryptography.hazmat.primitives import ciphers
 from cryptography.hazmat.primitives.ciphers.algorithms import (
     AES, Camellia, TripleDES, Blowfish, ARC4, CAST5, IDEA
 )
+from cryptography.hazmat.primitives.ciphers.modes import ECB
 
 
 class TestAES(object):
@@ -120,3 +123,10 @@ class TestIDEA(object):
     def test_invalid_key_size(self):
         with pytest.raises(ValueError):
             IDEA(b"\x00" * 17)
+
+
+def test_invalid_backend():
+    pretend_backend = object()
+
+    with pytest.raises(UnsupportedInterface):
+        ciphers.Cipher(AES(b"AAAAAAAAAAAAAAAA"), ECB, pretend_backend)
diff --git a/tests/hazmat/primitives/test_hashes.py b/tests/hazmat/primitives/test_hashes.py
index fc53d635..5b318f64 100644
--- a/tests/hazmat/primitives/test_hashes.py
+++ b/tests/hazmat/primitives/test_hashes.py
@@ -20,7 +20,10 @@ import pytest
 import six
 
 from cryptography import utils
-from cryptography.exceptions import AlreadyFinalized, UnsupportedHash
+from cryptography.exceptions import (
+    AlreadyFinalized, UnsupportedHash, UnsupportedInterface
+)
+from cryptography.hazmat.backends.interfaces import HashBackend
 from cryptography.hazmat.primitives import hashes, interfaces
 
 from .utils import generate_base_hash_test
@@ -39,7 +42,11 @@ class TestHashContext(object):
             m.update(six.u("\u00FC"))
 
     def test_copy_backend_object(self):
-        pretend_backend = pretend.stub()
+        @utils.register_interface(HashBackend)
+        class PretendBackend(object):
+            pass
+
+        pretend_backend = PretendBackend()
         copied_ctx = pretend.stub()
         pretend_ctx = pretend.stub(copy=lambda: copied_ctx)
         h = hashes.Hash(hashes.SHA1(), backend=pretend_backend,
@@ -171,3 +178,10 @@ class TestMD5(object):
         digest_size=16,
         block_size=64,
     )
+
+
+def test_invalid_backend():
+    pretend_backend = object()
+
+    with pytest.raises(UnsupportedInterface):
+        hashes.Hash(hashes.SHA1(), pretend_backend)
diff --git a/tests/hazmat/primitives/test_hmac.py b/tests/hazmat/primitives/test_hmac.py
index 88bed52c..3589e6ac 100644
--- a/tests/hazmat/primitives/test_hmac.py
+++ b/tests/hazmat/primitives/test_hmac.py
@@ -21,8 +21,9 @@ import six
 
 from cryptography import utils
 from cryptography.exceptions import (
-    AlreadyFinalized, UnsupportedHash, InvalidSignature
+    AlreadyFinalized, UnsupportedHash, InvalidSignature, UnsupportedInterface
 )
+from cryptography.hazmat.backends.interfaces import HMACBackend
 from cryptography.hazmat.primitives import hashes, hmac, interfaces
 
 from .utils import generate_base_hmac_test
@@ -52,8 +53,11 @@ class TestHMAC(object):
             h.update(six.u("\u00FC"))
 
     def test_copy_backend_object(self):
-        pretend_hmac = pretend.stub()
-        pretend_backend = pretend.stub(hmacs=pretend_hmac)
+        @utils.register_interface(HMACBackend)
+        class PretendBackend(object):
+            pass
+
+        pretend_backend = PretendBackend()
         copied_ctx = pretend.stub()
         pretend_ctx = pretend.stub(copy=lambda: copied_ctx)
         h = hmac.HMAC(b"key", hashes.SHA1(), backend=pretend_backend,
@@ -104,3 +108,10 @@ class TestHMAC(object):
     def test_unsupported_hash(self, backend):
         with pytest.raises(UnsupportedHash):
             hmac.HMAC(b"key", UnsupportedDummyHash(), backend)
+
+
+def test_invalid_backend():
+    pretend_backend = object()
+
+    with pytest.raises(UnsupportedInterface):
+        hmac.HMAC(b"key", hashes.SHA1(), pretend_backend)
diff --git a/tests/hazmat/primitives/test_rsa.py b/tests/hazmat/primitives/test_rsa.py
index 114dc415..0e88bb7f 100644
--- a/tests/hazmat/primitives/test_rsa.py
+++ b/tests/hazmat/primitives/test_rsa.py
@@ -21,9 +21,9 @@ import os
 import pytest
 
 from cryptography import exceptions, utils
+from cryptography.exceptions import UnsupportedInterface
 from cryptography.hazmat.primitives import hashes, interfaces
-from cryptography.hazmat.primitives.asymmetric import rsa
-from cryptography.hazmat.primitives.asymmetric import padding
+from cryptography.hazmat.primitives.asymmetric import rsa, padding
 
 from ...utils import load_pkcs1_vectors, load_vectors_from_file
 
@@ -385,6 +385,13 @@ class TestRSA(object):
             rsa.RSAPublicKey(public_exponent=6, modulus=15)
 
 
+def test_rsa_generate_invalid_backend():
+    pretend_backend = object()
+
+    with pytest.raises(UnsupportedInterface):
+        rsa.RSAPrivateKey.generate(65537, 2048, pretend_backend)
+
+
 @pytest.mark.rsa
 class TestRSASignature(object):
     @pytest.mark.parametrize(
@@ -444,6 +451,14 @@ class TestRSASignature(object):
         with pytest.raises(TypeError):
             private_key.signer("notpadding", hashes.SHA1(), backend)
 
+    def test_rsa_signer_invalid_backend(self, backend):
+        pretend_backend = object()
+        private_key = rsa.RSAPrivateKey.generate(65537, 2048, backend)
+
+        with pytest.raises(UnsupportedInterface):
+            private_key.signer(
+                padding.PKCS1v15(), hashes.SHA256, pretend_backend)
+
 
 @pytest.mark.rsa
 class TestRSAVerification(object):
@@ -559,6 +574,15 @@ class TestRSAVerification(object):
         with pytest.raises(TypeError):
             public_key.verifier(b"sig", "notpadding", hashes.SHA1(), backend)
 
+    def test_rsa_verifier_invalid_backend(self, backend):
+        pretend_backend = object()
+        private_key = rsa.RSAPrivateKey.generate(65537, 2048, backend)
+        public_key = private_key.public_key()
+
+        with pytest.raises(UnsupportedInterface):
+            public_key.verifier(
+                b"foo", padding.PKCS1v15(), hashes.SHA256(), pretend_backend)
+
 
 class TestMGF1(object):
     def test_invalid_hash_algorithm(self):