diff --git a/tests/run-multitests.py b/tests/run-multitests.py
index ad032df38b23..5b8e70e921a7 100755
--- a/tests/run-multitests.py
+++ b/tests/run-multitests.py
@@ -389,7 +389,7 @@ def run_tests(test_files, instances_truth, instances_test):
                 print("### TRUTH ###")
                 print(output_truth, end="")
                 print("### DIFF ###")
-                print_diff(output_test, output_truth)
+                print_diff(output_truth, output_test)
 
         if cmd_args.show_output:
             print()