diff --git a/tests/mock-bad-wflinfo.c b/tests/mock-bad-wflinfo.c
index 2311ddb839299f78c4b8e9421152b2b03e0a5067..9f9d46c5c25fce4f085b375686a9af01841c3310 100644
--- a/tests/mock-bad-wflinfo.c
+++ b/tests/mock-bad-wflinfo.c
@@ -30,7 +30,10 @@ main (int argc,
       char **argv)
 {
   // Give bad output
+  fprintf (stderr, "warning: this warning should always be logged\n");
+
   fprintf (stderr, "Waffle error: 0x2 WAFFLE_ERROR_UNKNOWN: XOpenDisplay failed\n");
+
   return 1;
 }
 
diff --git a/tests/mock-software-wflinfo.c b/tests/mock-software-wflinfo.c
index ed03f69a087a4e1b149f733de3e7199ee475d3d1..1d7bf70a2ff9c8b2299277c97eae641e0f91cc6d 100644
--- a/tests/mock-software-wflinfo.c
+++ b/tests/mock-software-wflinfo.c
@@ -40,6 +40,7 @@ main (int argc,
           "\",\n\t\t\"shading language version string\": \"1.40\",\n"
           "\t\t\"extensions\": [\n"
           "\t\t]\n\t}\n}\n");
+  fprintf (stderr, "warning: this warning should always be logged\n");
   return 0;
 }