在Go中使用模拟功能 [英] Mock functions in Go
问题描述
我通过编写一个小型个人项目来学习Go。虽然它很小,但我决定从一开始就进行严格的单元测试,以在Go上学习良好的习惯。
平凡的单元测试都很好,很花哨,现在困扰于依赖关系;我希望能够用模拟函数替换一些函数调用。以下是我的代码片段:
func get_page(url字符串)字符串{
get_dl_slot(url)
推迟free_dl_slot(url)
resp,err:= http.Get(url)
if err!= nil {return}
defer resp.Body.Close( )
内容,错误:= ioutil.ReadAll(resp.Body)
if err!= nil {return}
返回字符串(内容)
}
func下载器(){
dl_slots = make(chan bool,DL_SLOT_AMOUNT)//初始化下载插槽信号量
content:= get_page(BASE_URL)
links_regexp: = regexp.MustCompile(LIST_LINK_REGEXP)
匹配:= links_regexp.FindAllStringSubmatch(content,-1)
for _,match:=范围匹配{
go serie_dl(match [1],match [ 2])
}
}
我希望能够测试downloader()而不通过http实际获取页面 - 即通过嘲弄get_page(更容易,因为它只返回页面内容作为st ring)或http.Get()。
我发现这个主题: https://groups.google.com/forum/#!topic/golang-nuts/6AN1E2CJOxI 这似乎是一个类似的问题。 Julian Phillips将他的图书馆Withmock( http://github.com/qur/withmock )作为解决方案,但我是无法让它工作。以下是我的测试代码的相关部分,这是对我来说主要是货物邪教代码,说实话:
$ b
import(
测试
净/ http//模拟
code.google.com/p/gomock
)
...
func TestDownloader (t * testing.T){
ctrl:= gomock.NewController()
推迟ctrl.Finish()
http.MOCK()。SetController(ctrl)
http。 EXPECT()。Get(BASE_URL)
downloader()
//其余的被写入
}
测试输出如下:
错误:未能安装'_et / http' :退出状态1
输出:
无法加载软件包:package _et / http:在/ var / folders / z9 / ql_yn5h550s6shtb9c5sggj40000gn中找到软件包http(chunked.go)和main(main_mock.go) T / withmock570825607 / path / src / _et / http
Withmock是我测试问题的解决方案吗?我应该怎么做才能使它工作?
:)
就个人而言,我不使用 gomock
(或者任何模拟框架;嘲笑Go没有它很容易)。我要么将依赖项传递给 downloader()
函数作为参数,要么将 get_page
依赖项:方法1:传递 get_page()
作为下载程序()的参数
类型PageGetter func(url字符串)字符串
func下载器(pageGetterFunc PageGetter){
// ...
content:= pageGetterFunc(BASE_URL)
// ...
}
主营:
func get_page(url string)string {/ * ... * /}
func main(){
downloader(get_page)
}
测试:
$ b
func mock_get_page(url string)string {
//模拟您的'get_page()'函数
func TestDownloader(t * testing.T){
downloader(mock_get_page)
}
方法2:制作 download()
类型下载器的方法
:
如果您不想将依赖项作为参数传递,也可以使 get_page()
类型的成员,并使 download()
该类型的方法,然后可以使用 get_page < code $ c
$ b $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $'
get_page PageGetter
}
func NewDownloader(pg PageGetter)* Downloader {
return& Downloader {get_page:pg}
}
func(d * Downloader)下载(){
// ...
内容:= d.get_page(BASE_URL)
// ...
}
主营:
func get_page(url string)string {/ * ... * /}
func main(){
d:= NewDownloader(get_page )
d.download()
}
测试:< /强>
func mock_get_page(url string)string {
//模拟您的'get_page()'函数
}
$ b $ func TestDownloader(){
d:= NewDownloader(mock_get_page)
d.download()
}
I'm learning Go by coding a small personal project. Even though it's small, I decided to do rigorous unit testing to learn good habits on Go right from the start.
Trivial unit tests were all fine and dandy, but I'm puzzled with dependencies now; I want to be able to replace some function calls with mock ones. Here's a snippet of my code:
func get_page(url string) string {
get_dl_slot(url)
defer free_dl_slot(url)
resp, err := http.Get(url)
if err != nil { return "" }
defer resp.Body.Close()
contents, err := ioutil.ReadAll(resp.Body)
if err != nil { return "" }
return string(contents)
}
func downloader() {
dl_slots = make(chan bool, DL_SLOT_AMOUNT) // Init the download slot semaphore
content := get_page(BASE_URL)
links_regexp := regexp.MustCompile(LIST_LINK_REGEXP)
matches := links_regexp.FindAllStringSubmatch(content, -1)
for _, match := range matches{
go serie_dl(match[1], match[2])
}
}
I'd like to be able to test downloader() without actually getting a page through http - i.e. by mocking either get_page (easier since it returns just the page content as a string) or http.Get().
I found this thread: https://groups.google.com/forum/#!topic/golang-nuts/6AN1E2CJOxI which seems to be about a similar problem. Julian Phillips presents his library, Withmock (http://github.com/qur/withmock) as a solution, but I'm unable to get it to work. Here's the relevant parts of my testing code, which is largely cargo cult code to me, to be honest:
import (
"testing"
"net/http" // mock
"code.google.com/p/gomock"
)
...
func TestDownloader (t *testing.T) {
ctrl := gomock.NewController()
defer ctrl.Finish()
http.MOCK().SetController(ctrl)
http.EXPECT().Get(BASE_URL)
downloader()
// The rest to be written
}
The test output is following:
ERROR: Failed to install '_et/http': exit status 1
output:
can't load package: package _et/http: found packages http (chunked.go) and main (main_mock.go) in /var/folders/z9/ql_yn5h550s6shtb9c5sggj40000gn/T/withmock570825607/path/src/_et/http
Is the Withmock a solution to my testing problem? What should I do to get it to work?
Kudos to you for practicing good testing! :)
Personally, I don't use gomock
(or any mocking framework for that matter; mocking in Go is very easy without it). I would either pass a dependency to the downloader()
function as a parameter, or I would make downloader()
a method on a type, and the type can hold the get_page
dependency:
Method 1: Pass get_page()
as a parameter of downloader()
type PageGetter func(url string) string
func downloader(pageGetterFunc PageGetter) {
// ...
content := pageGetterFunc(BASE_URL)
// ...
}
Main:
func get_page(url string) string { /* ... */ }
func main() {
downloader(get_page)
}
Test:
func mock_get_page(url string) string {
// mock your 'get_page()' function here
}
func TestDownloader(t *testing.T) {
downloader(mock_get_page)
}
Method2: Make download()
a method of a type Downloader
:
If you don't want to pass the dependency as a parameter, you could also make get_page()
a member of a type, and make download()
a method of that type, which can then use get_page
:
type PageGetter func(url string) string
type Downloader struct {
get_page PageGetter
}
func NewDownloader(pg PageGetter) *Downloader {
return &Downloader{get_page: pg}
}
func (d *Downloader) download() {
//...
content := d.get_page(BASE_URL)
//...
}
Main:
func get_page(url string) string { /* ... */ }
func main() {
d := NewDownloader(get_page)
d.download()
}
Test:
func mock_get_page(url string) string {
// mock your 'get_page()' function here
}
func TestDownloader() {
d := NewDownloader(mock_get_page)
d.download()
}
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