Return help diff error
diff --git a/help_test.go b/help_test.go
index fc958cd..8f4131c 100644
--- a/help_test.go
+++ b/help_test.go
@@ -38,7 +38,7 @@
 	os.Remove(atmp.Name())
 	os.Remove(btmp.Name())
 
-	return string(ret), nil
+	return string(ret), err
 }
 
 type helpOptions struct {