diff --git a/ChangeLog b/ChangeLog
index e3109e10b7..e956238910 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2017-04-22  Bruno Haible  <bruno@clisp.org>
+
+	sys_file tests: Avoid warning.
+	* tests/test-sys_file.c (main): Add a default clause to the switch
+	statement.
+
 2017-04-22  Bruno Haible  <bruno@clisp.org>
 
 	sethostname: Update doc.
diff --git a/tests/test-sys_file.c b/tests/test-sys_file.c
index 3be1e57976..6394c7779e 100644
--- a/tests/test-sys_file.c
+++ b/tests/test-sys_file.c
@@ -30,6 +30,8 @@ main (void)
     case LOCK_NB:
     case LOCK_UN:
       ;
+    default:
+      ;
     }
   return 0;
 }