PBKDF2 support for OpenSSL backend
diff --git a/pytest.ini b/pytest.ini
index 36d4edc..89fda53 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -1,7 +1,8 @@
 [pytest]
 addopts = -r s
 markers =
-    hmac: this test requires a backend providing HMACBackend
     cipher: this test requires a backend providing CipherBackend
     hash: this test requires a backend providing HashBackend
+    hmac: this test requires a backend providing HMACBackend
+    pbkdf2: this test requires a backend providing PBKDF2Backend
     supported: parametrized test requiring only_if and skip_message