You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: truncate_test.go
    path of file: ./repos/gitea/modules/util
    
    the code of the file until where you have to start completion: // Copyright 2021 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package util

import (
	"testing"

	"github.com/stretchr/testify/assert"
)

func TestSplitString(t *testing.T) {
	type testCase struct {
		input    string
		n        int
		leftSub  string
		ellipsis string
	}

	test := func(tc []*testCase, f func(input string, n int) (left, right string)) {
		for _, c := range tc {
			l, r := f(c.input, c.n)
			if c.ellipsis != "" {
				assert.Equal(t, c.leftSub+c.ellipsis, l, "test split %q at %d, expected leftSub: %q", c.input, c.n, c.leftSub)
				assert.Equal(t, c.ellipsis+c.input[len(c.leftSub):], r, "test split %s at %d, expected rightSub: %q", c.input, c.n, c.input[len(c.leftSub):])
			} else {
				assert.Equal(t, c.leftSub, l, "t
    
func TestSplitString(t *testing.T) {
	type testCase struct {
		input    string
		n        int
		leftSub  string
		ellipsis string
	}

	test := func(tc []*testCase, f func(input string, n int) (left, right string)) {
		for _, c := range tc {
			l, r := f(c.input, c.n)
			if c.ellipsis != "" {
				assert.Equal(t, c.leftSub+c.ellipsis, l, "test split %q at %d, expected leftSub: %q", c.input, c.n, c.leftSub)
				assert.Equal(t, c.ellipsis+c.input[len(c.leftSub):], r, "test split %s at %d, expected rightSub: %q", c.input, c.n, c.input[len(c.leftSub):])
			} else {
				assert.Equal(t, c.leftSub, l, "test split %q at %d, expected leftSub: %q", c.input, c.n, c.leftSub)
				assert.Empty(t, r, "test split %q at %d, expected rightSub: %q", c.input, c.n, "")
			}
		}
	}

	tc := []*testCase{
		{"abc123xyz", 0, "", utf8Ellipsis},
		{"abc123xyz", 1, "", utf8Ellipsis},
		{"abc123xyz", 4, "a", utf8Ellipsis},
		{"啊bc123xyz", 4, "", utf8Ellipsis},
		{"啊bc123xyz", 6, "啊", utf8Ellipsis},
		{"啊bc", 5, "啊bc", ""},
		{"啊bc", 6, "啊bc", ""},
		{"abc\xef\x03\xfe", 3, "", asciiEllipsis},
		{"abc\xef\x03\xfe", 4, "a", asciiEllipsis},
		{"\xef\x03", 1, "\xef\x03", ""},
	}
	test(tc, SplitStringAtByteN)
}