diff --git a/tests/hwsim/README b/tests/hwsim/README
index 3b2d7ce19..aa56ea285 100644
--- a/tests/hwsim/README
+++ b/tests/hwsim/README
@@ -181,6 +181,7 @@ CREATE TABLE results (test,result,run,time,duration,build,commitid);
 CREATE INDEX results_idx ON results (test);
 CREATE INDEX results_idx2 ON results (run);
 CREATE TABLE tests (test,description);
+CREATE UNIQUE INDEX tests_idx ON tests (test);
 CREATE TABLE logs (test,run,type,contents);
 CREATE INDEX logs_idx ON logs (test);
 CREATE INDEX logs_idx2 ON logs (run);