Use keyword argument forms everywhere.
diff --git a/tests/hazmat/primitives/test_hashes.py b/tests/hazmat/primitives/test_hashes.py
index 321082f..c8719b0 100644
--- a/tests/hazmat/primitives/test_hashes.py
+++ b/tests/hazmat/primitives/test_hashes.py
@@ -27,7 +27,7 @@
 
 class TestHashContext(object):
     def test_hash_reject_unicode(self, backend):
-        m = hashes.Hash(hashes.SHA1(), backend)
+        m = hashes.Hash(hashes.SHA1(), backend=backend)
         with pytest.raises(TypeError):
             m.update(six.u("\u00FC"))
 
@@ -35,16 +35,16 @@
         pretend_backend = pretend.stub()
         copied_ctx = pretend.stub()
         pretend_ctx = pretend.stub(copy=lambda: copied_ctx)
-        h = hashes.Hash(hashes.SHA1(), pretend_backend, ctx=pretend_ctx)
+        h = hashes.Hash(hashes.SHA1(), backend=pretend_backend, ctx=pretend_ctx)
         assert h._backend is pretend_backend
         assert h.copy()._backend is h._backend
 
     def test_hash_algorithm_instance(self, backend):
         with pytest.raises(TypeError):
-            hashes.Hash(hashes.SHA1, backend)
+            hashes.Hash(hashes.SHA1, backend=backend)
 
     def test_raises_after_finalize(self, backend):
-        h = hashes.Hash(hashes.SHA1(), backend)
+        h = hashes.Hash(hashes.SHA1(), backend=backend)
         h.finalize()
 
         with pytest.raises(AlreadyFinalized):
diff --git a/tests/hazmat/primitives/test_hmac.py b/tests/hazmat/primitives/test_hmac.py
index 622f186..992bcb1 100644
--- a/tests/hazmat/primitives/test_hmac.py
+++ b/tests/hazmat/primitives/test_hmac.py
@@ -33,7 +33,7 @@
     )
 
     def test_hmac_reject_unicode(self, backend):
-        h = hmac.HMAC(b"mykey", hashes.SHA1(), backend)
+        h = hmac.HMAC(b"mykey", hashes.SHA1(), backend=backend)
         with pytest.raises(TypeError):
             h.update(six.u("\u00FC"))
 
@@ -42,16 +42,17 @@
         pretend_backend = pretend.stub(hmacs=pretend_hmac)
         copied_ctx = pretend.stub()
         pretend_ctx = pretend.stub(copy=lambda: copied_ctx)
-        h = hmac.HMAC(b"key", hashes.SHA1(), pretend_backend, ctx=pretend_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
 
     def test_hmac_algorithm_instance(self, backend):
         with pytest.raises(TypeError):
-            hmac.HMAC(b"key", hashes.SHA1, backend)
+            hmac.HMAC(b"key", hashes.SHA1, backend=backend)
 
     def test_raises_after_finalize(self, backend):
-        h = hmac.HMAC(b"key", hashes.SHA1(), backend)
+        h = hmac.HMAC(b"key", hashes.SHA1(), backend=backend)
         h.finalize()
 
         with pytest.raises(AlreadyFinalized):
diff --git a/tests/hazmat/primitives/utils.py b/tests/hazmat/primitives/utils.py
index c476a75..6c67ddb 100644
--- a/tests/hazmat/primitives/utils.py
+++ b/tests/hazmat/primitives/utils.py
@@ -42,7 +42,7 @@
     cipher = Cipher(
         cipher_factory(**params),
         mode_factory(**params),
-        backend
+        backend=backend
     )
     encryptor = cipher.encryptor()
     actual_ciphertext = encryptor.update(binascii.unhexlify(plaintext))
@@ -82,7 +82,7 @@
     plaintext = params.pop("plaintext")
     ciphertext = params.pop("ciphertext")
     offset = params.pop("offset")
-    cipher = Cipher(cipher_factory(**params), None, backend)
+    cipher = Cipher(cipher_factory(**params), None, backend=backend)
     encryptor = cipher.encryptor()
     # throw away offset bytes
     encryptor.update(b"\x00" * int(offset))
@@ -121,7 +121,7 @@
         pytest.skip(skip_message)
     msg = params[0]
     md = params[1]
-    m = hashes.Hash(algorithm, backend)
+    m = hashes.Hash(algorithm, backend=backend)
     m.update(binascii.unhexlify(msg))
     expected_md = md.replace(" ", "").lower().encode("ascii")
     assert m.finalize() == binascii.unhexlify(expected_md)
@@ -148,7 +148,7 @@
     if only_if is not None and not only_if(backend):
         pytest.skip(skip_message)
 
-    m = hashes.Hash(algorithm, backend)
+    m = hashes.Hash(algorithm, backend=backend)
     assert m.algorithm.digest_size == digest_size
     assert m.algorithm.block_size == block_size
     m_copy = m.copy()
@@ -180,7 +180,7 @@
 def long_string_hash_test(backend, algorithm, md, only_if, skip_message):
     if only_if is not None and not only_if(backend):
         pytest.skip(skip_message)
-    m = hashes.Hash(algorithm, backend)
+    m = hashes.Hash(algorithm, backend=backend)
     m.update(b"a" * 1000000)
     assert m.finalize() == binascii.unhexlify(md.lower().encode("ascii"))
 
@@ -211,7 +211,7 @@
     msg = params[0]
     md = params[1]
     key = params[2]
-    h = hmac.HMAC(binascii.unhexlify(key), algorithm, backend)
+    h = hmac.HMAC(binascii.unhexlify(key), algorithm, backend=backend)
     h.update(binascii.unhexlify(msg))
     assert h.finalize() == binascii.unhexlify(md.encode("ascii"))
 
@@ -233,7 +233,7 @@
     if only_if is not None and not only_if(backend):
         pytest.skip(skip_message)
     key = b"ab"
-    h = hmac.HMAC(binascii.unhexlify(key), algorithm, backend)
+    h = hmac.HMAC(binascii.unhexlify(key), algorithm, backend=backend)
     h_copy = h.copy()
     assert h != h_copy
     assert h._ctx != h_copy._ctx