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: filehelper_test.go
    path of file: ./repos/gaia/helper/filehelper
    
    the code of the file until where you have to start completion: package filehelper

import (
	"bytes"
	"crypto/sha256"
	"io/ioutil"
	"os"
	"path/filepath"
	"testing"
)

func TestGetSHA256Sum(t *testing.T) {
	tmp, _ := ioutil.TempDir("", "TestGetSHA256Sum")
	sumText := []byte("hello world\n")
	filePath := filepath.Join(tmp, "test.file")
	err := ioutil.WriteFile(filePath, sumText, 0777)
	if err != nil {
		t
    
func TestCopyFileContents(t *testing.T) {
	tmp, _ := ioutil.TempDir("", "TestCopyFileContents")
	sumText := []byte("hello world\n")
	filePath := filepath.Join(tmp, "test.file")
	err := ioutil.WriteFile(filePath, sumText, 0777)
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(tmp)
	calcSha, err := GetSHA256Sum(filePath)
	if err != nil {
		t.Fatal(err)
	}
	output := filepath.Join(tmp, "copy.file")
	if err := CopyFileContents(filePath, output); err != nil {
		t.Fatal(err)
	}
	copySha, err := GetSHA256Sum(output)
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(copySha, calcSha) {
		t.Fatal("bytes are not identical")
	}
}