diff --git a/runtests.go b/runtests.go
index d2a36ee..78da953 100644
--- a/runtests.go
+++ b/runtests.go
@@ -36,12 +36,13 @@ func runOneTest(dir string, test *CPTest) {
 	defer inpipe.Close();
 
 	fmt.Fprintln(inpipe, string(*test.Input));
-	out,err := cmd.Output(); 
+	out,err := cmd.CombinedOutput();
+	fmt.Println("OUTPUT:")
 	if err != nil {
 		fmt.Println(err);
+		fmt.Println(string(out));
 		return
 	}
-	fmt.Println("OUTPUT:")
 	fmt.Println(string(out));
 
 	if test.Output != nil {