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: is-1.7_test.go
    path of file: ./repos/is
    
    the code of the file until where you have to start completion: //go:build go1.7
// +build go1.7

package is

import (
	"bytes"
	"strings"
	"testing"
)

// TestSubtests ensures subtests work as expected.
// https://github.com/matryer/is/issues/1
func TestSubtests(t *testing.T) {
	t.Run("sub1", func(t *testing.T) {
		is := New(t)
		is.Equal(1+1, 2)
	})
}

func TestHelper(t *testing.T) {
	tests := []struct {
		name             string
		helper           bool
		expectedFilename string
	}{
		{
		
    
func TestHelper(t *testing.T) {
	tests := []struct {
		name             string
		helper           bool
		expectedFilename string
	}{
		{
			name:             "without helper",
			helper:           false,
			expectedFilename: "is_helper_test.go",
		},
		{
			name:             "with helper",
			helper:           true,
			expectedFilename: "is-1.7_test.go",
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			tt := &mockT{}
			is := NewRelaxed(tt)

			var buf bytes.Buffer
			is.out = &buf
			helper(is, tc.helper)
			actual := buf.String()
			t.Log(actual)
			if !strings.Contains(actual, tc.expectedFilename) {
				t.Errorf("string does not contain correct filename: %s", actual)
			}
		})
	}
}