diff --git a/artiq/test/sync_struct.py b/artiq/test/sync_struct.py
index ece90360b..e5e950535 100644
--- a/artiq/test/sync_struct.py
+++ b/artiq/test/sync_struct.py
@@ -17,15 +17,17 @@ def write_test_data(test_dict):
     for key, value in enumerate(test_values):
         test_dict[key] = value
     test_dict[1.5] = 1.5
-    test_dict["array"] = []
-    test_dict["array"].append(42)
-    test_dict["array"].insert(1, 1)
+    test_dict["list"] = []
+    test_dict["list"].append(42)
+    test_dict["list"].insert(1, 1)
     test_dict[100] = 0
     test_dict[100] = 1
     test_dict[101] = 1
     test_dict.pop(101)
     test_dict[102] = 1
     del test_dict[102]
+    test_dict["array"] = np.zeros(1)
+    test_dict["array"][0] = 10
     test_dict["finished"] = True