1 files changed, 21 insertions, 0 deletions
diff --git a/tests/hazmat/bindings/test_openssl.py b/tests/hazmat/bindings/test_openssl.py
index e6604e6b..1eb6f200 100644
--- a/tests/hazmat/bindings/test_openssl.py
+++ b/tests/hazmat/bindings/test_openssl.py
@@ -74,3 +74,24 @@ class TestOpenSSL(object):
         )
         with pytest.raises(UnsupportedAlgorithm):
             cipher.encryptor()
+
+    def test_handle_unknown_error(self):
+        with pytest.raises(SystemError):
+            backend._handle_error_code(0, 0, 0)
+
+        with pytest.raises(SystemError):
+            backend._handle_error_code(backend.lib.ERR_LIB_EVP, 0, 0)
+
+        with pytest.raises(SystemError):
+            backend._handle_error_code(
+                backend.lib.ERR_LIB_EVP,
+                backend.lib.EVP_F_EVP_ENCRYPTFINAL_EX,
+                0
+            )
+
+        with pytest.raises(SystemError):
+            backend._handle_error_code(
+                backend.lib.ERR_LIB_EVP,
+                backend.lib.EVP_F_EVP_DECRYPTFINAL_EX,
+                0
+            )