diff --git a/tests/test_data/hyperion_parameters.json b/tests/test_data/hyperion_parameters.json
index 0426dc3b8..e497198fc 100644
--- a/tests/test_data/hyperion_parameters.json
+++ b/tests/test_data/hyperion_parameters.json
@@ -18,7 +18,7 @@
         "det_dist_to_beam_converter_path": "tests/test_data/test_lookup_table.txt",
         "trigger_mode": 2,
         "detector_size_constants": "EIGER2_X_16M",
-        "beam_xy_converter": null,
+        "beam_xy_converter": null
     },
     "ispyb_params": {
         "visit_path": "/tmp/cm31105-4/",