From da3c9eeebd0302584ccc2031a8ab917779d04ce9 Mon Sep 17 00:00:00 2001
From: 5ouma <101255979+5ouma@users.noreply.github.com>
Date: Fri, 1 Sep 2023 15:31:11 +0900
Subject: [PATCH] [update] Test for `SetErrPrefix()`

If it doesn't output any errors, fails the test.
---
 command_test.go | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/command_test.go b/command_test.go
index b0f5e860..d234b355 100644
--- a/command_test.go
+++ b/command_test.go
@@ -1099,6 +1099,18 @@ func TestShorthandVersionTemplate(t *testing.T) {
 	checkStringContains(t, output, "customized version: 1.0.0")
 }
 
+func TestErrPrefix(t *testing.T) {
+	rootCmd := &Command{Use: "root", SilenceUsage: true, Run: emptyRun}
+	rootCmd.SetErrPrefix("customized error prefix:")
+
+	output, err := executeCommand(rootCmd, "--unknown", "flag")
+	if err == nil {
+		t.Errorf("Expected error")
+	}
+
+	checkStringContains(t, output, "customized error prefix: unknown flag: --unknown")
+}
+
 func TestVersionFlagExecutedOnSubcommand(t *testing.T) {
 	rootCmd := &Command{Use: "root", Version: "1.0.0"}
 	rootCmd.AddCommand(&Command{Use: "sub", Run: emptyRun})