diff --git a/todoist/id_test.go b/todoist/id_test.go
index 3341a1e..d43f37e 100644
--- a/todoist/id_test.go
+++ b/todoist/id_test.go
@@ -25,7 +25,7 @@ var testIDs = []struct {
 	{
 		"invalid",
 		"",
-		errors.New("Invalid ID: invalid"),
+		errors.New("invalid id: invalid"),
 	},
 }