1 files changed, 49 insertions, 1 deletions
diff --git a/tests/hazmat/backends/test_multibackend.py b/tests/hazmat/backends/test_multibackend.py
index f300b6c8..03b3187b 100644
--- a/tests/hazmat/backends/test_multibackend.py
+++ b/tests/hazmat/backends/test_multibackend.py
@@ -15,8 +15,9 @@ import pytest
 
 from cryptography.exceptions import UnsupportedAlgorithm
 from cryptography.hazmat.backends.multibackend import PrioritizedMultiBackend
-from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives import hashes, hmac
 from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
+from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
 
 
 class DummyCipherBackend(object):
@@ -47,6 +48,31 @@ class DummyHashBackend(object):
             raise UnsupportedAlgorithm
 
 
+class DummyHMACBackend(object):
+    def __init__(self, supported_algorithms):
+        self._algorithms = supported_algorithms
+
+    def hmac_supported(self, algorithm):
+        return type(algorithm) in self._algorithms
+
+    def create_hmac_ctx(self, key, algorithm):
+        if not self.hmac_supported(algorithm):
+            raise UnsupportedAlgorithm
+
+
+class DummyPBKDF2HMAC(object):
+    def __init__(self, supported_algorithms):
+        self._algorithms = supported_algorithms
+
+    def pbkdf2_hmac_supported(self, algorithm):
+        return type(algorithm) in self._algorithms
+
+    def derive_pbkdf2_hmac(self, algorithm, length, salt, iterations,
+                           key_material):
+        if not self.pbkdf2_hmac_supported(algorithm):
+            raise UnsupportedAlgorithm
+
+
 
 class TestPrioritizedMultiBackend(object):
     def test_ciphers(self):
@@ -87,3 +113,25 @@ class TestPrioritizedMultiBackend(object):
 
         with pytest.raises(UnsupportedAlgorithm):
             hashes.Hash(hashes.SHA1(), backend=backend)
+
+    def test_hmac(self):
+        backend = PrioritizedMultiBackend([
+            DummyHMACBackend([hashes.MD5])
+        ])
+        assert backend.hmac_supported(hashes.MD5())
+
+        hmac.HMAC(b"", hashes.MD5(), backend=backend)
+
+        with pytest.raises(UnsupportedAlgorithm):
+            hmac.HMAC(b"", hashes.SHA1(), backend=backend)
+
+    def test_pbkdf2(self):
+        backend = PrioritizedMultiBackend([
+            DummyPBKDF2HMAC([hashes.MD5])
+        ])
+        assert backend.pbkdf2_hmac_supported(hashes.MD5())
+
+        backend.derive_pbkdf2_hmac(hashes.MD5(), 10, b"", 10, b"")
+
+        with pytest.raises(UnsupportedAlgorithm):
+            backend.derive_pbkdf2_hmac(hashes.SHA1(), 10, b"", 10, b"")