diff --git a/cryptography/utils.py b/cryptography/utils.py
index 9c57408..f4c2e3c 100644
--- a/cryptography/utils.py
+++ b/cryptography/utils.py
@@ -17,6 +17,7 @@
 
 
 DeprecatedIn05 = DeprecationWarning
+DeprecatedIn06 = PendingDeprecationWarning
 
 
 def register_interface(iface):
diff --git a/pytest.ini b/pytest.ini
index 00a2c7f..77e7396 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -12,3 +12,4 @@
     pkcs8_serialization: this test requires a backend providing PKCS8SerializationBackend
     supported: parametrized test requiring only_if and skip_message
     elliptic: this test requires a backend providing EllipticCurveBackend
+    pem_serialization: this test requires a backend providing PEMSerializationBackend
diff --git a/tests/conftest.py b/tests/conftest.py
index af14638..b7981c9 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -18,7 +18,8 @@
 from cryptography.hazmat.backends import _available_backends
 from cryptography.hazmat.backends.interfaces import (
     CMACBackend, CipherBackend, DSABackend, EllipticCurveBackend, HMACBackend,
-    HashBackend, PBKDF2HMACBackend, PKCS8SerializationBackend, RSABackend,
+    HashBackend, PBKDF2HMACBackend, PEMSerializationBackend,
+    PKCS8SerializationBackend, RSABackend,
     TraditionalOpenSSLSerializationBackend
 )
 from .utils import check_backend_support, check_for_iface, select_backends
@@ -48,6 +49,7 @@
     )
     check_for_iface("pkcs8_serialization", PKCS8SerializationBackend, item)
     check_for_iface("elliptic", EllipticCurveBackend, item)
+    check_for_iface("pem_serialization", PEMSerializationBackend, item)
     check_backend_support(item)
 
 
diff --git a/tests/hazmat/primitives/test_serialization.py b/tests/hazmat/primitives/test_serialization.py
index e960878..9333a6b 100644
--- a/tests/hazmat/primitives/test_serialization.py
+++ b/tests/hazmat/primitives/test_serialization.py
@@ -22,7 +22,7 @@
 from cryptography.exceptions import _Reasons
 from cryptography.hazmat.primitives import interfaces
 from cryptography.hazmat.primitives.serialization import (
-    load_pem_private_key, load_pem_pkcs8_private_key,
+    load_pem_pkcs8_private_key, load_pem_private_key,
     load_pem_traditional_openssl_private_key
 )