diff --git a/subprojects/gst-rtsp-server/tests/check/gst/onvif.c b/subprojects/gst-rtsp-server/tests/check/gst/onvif.c
index 610c503413..c93d15f0c8 100644
--- a/subprojects/gst-rtsp-server/tests/check/gst/onvif.c
+++ b/subprojects/gst-rtsp-server/tests/check/gst/onvif.c
@@ -173,6 +173,9 @@ test_src_create (GstPushSrc * psrc, GstBuffer ** buffer)
     case FRAME_TYPE_B:
       buf_size = 5;
       break;
+    default:
+      g_assert_not_reached ();
+      return GST_FLOW_ERROR;
   }
 
   *buffer = gst_buffer_new_allocate (NULL, buf_size, NULL);