Add DSABackend
diff --git a/pytest.ini b/pytest.ini
index 3f65e30..b590d0b 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -2,6 +2,7 @@
 addopts = -r s
 markers =
     cipher: this test requires a backend providing CipherBackend
+    dsa: this test requires a backend providing DSABackend
     hash: this test requires a backend providing HashBackend
     hmac: this test requires a backend providing HMACBackend
     pbkdf2hmac: this test requires a backend providing PBKDF2HMACBackend