Name	Name	Last commit message	Last commit date
parent directory ..
assets	assets
README.md	README.md
main.go	main.go
main_test.go	main_test.go

HOW TO TESTING

测试的作用：

验证代码是否符合预期
资源竞争检查：race detect
调优：profiling：memory/cpu

原始代码

代码功能：访客记次数。

package main

import (
	"fmt"
	"log"
	"net/http"
)

var counter = map[string]int{}

func handleHello(w http.ResponseWriter, r *http.Request) {
	name := r.FormValue("name")
	counter[name]++

	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	w.Write([]byte("<h1 style='color: " + r.FormValue("color") +
		"'>Welcome!</h1> <p>Name: " + name + "</p> <p>Count: " + fmt.Sprint(counter[name]) + "</p>"))
}

func main() {
	http.HandleFunc("/hello", handleHello)
	log.Fatal(http.ListenAndServe(":8080", nil))
}

运行：

go run main.go

浏览器访问：

本地日志记录：

测试规范

运行测试：
1. 测试：go test
2. 压力测试：go test -bench
3. 测试覆盖：go test -cover
测试规范：
1. 测试函数示例
```
// go test or go test -v
func TestXxx(*testing.T)

// go test -bench
func BenchmarkXxx(*testing.B)
```
  Xxx不能以小写字母开头。
2. 测试文件规范：文件名以_test.go结尾。
3. 在测试函数里面使用：Error，Fail或者相关的函数标示相关错误。

例子：

单元测试：

func TestTimeConsuming(t *testing.T) {
    if testing.Short() {
        t.Skip("skipping test in short mode.")
    }
    ...
}

压力测试：

func BenchmarkHello(b *testing.B) {
    for i := 0; i < b.N; i++ {
        fmt.Sprintf("hello")
    }
}

Examples：

func ExampleHello() {
    fmt.Println("hello")
    // Output: hello
}

func ExampleSalutations() {
    fmt.Println("hello, and")
    fmt.Println("goodbye")
    // Output:
    // hello, and
    // goodbye
}

测试用例

运行测试

使用go test运行测试。

➜  how_to_test git:(how_to_test) ✗ go test
?       _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test      [no test files]

也可以使用Golang的TDD小工具：goconvey

安装：go get github.com/smartystreets/goconvey

介绍: GoConvey is awesome Go testing

运行：goconvey

效果截图：

测试用例

创建main_test.go，

touch main_test.go

编写第一个测试用例：

func TestHelloHandleFunc(t *testing.T) {
	rw := httptest.NewRecorder()
	name := "zouying"
	req := httptest.NewRequest(http.MethodPost, "/hello?name="+name, nil)
	handleHello(rw, req)

	if rw.Code != http.StatusOK {
		t.Errorf("status code not ok, status code is %v", rw.Code)
	}

	if len(counter) != 1 {
		t.Errorf("counter len not correct")
	}

	if counter[name] != 1 {
		t.Errorf("counter value is error: visitor=%s count=%v", name, counter[name])
	}
}

运行测试：go test -v：

➜ how_to_test git:(how_to_test) ✗ go test -v === RUN TestHelloHandleFunc INFO[0000] visited count=1 module=main name=zouying --- PASS: TestHelloHandleFunc (0.00s) PASS ok _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test 0.015s

运行测试覆盖：go test -cover

➜ how_to_test git:(how_to_test) ✗ go test -cover INFO[0000] visited count=1 module=main name=zouying PASS coverage: 62.5% of statements ok _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test 0.021s

查看覆盖的代码：

#!/bin/bash
go test -coverprofile=coverage.out
go tool cover -html=coverage.out

➜ how_to_test git:(how_to_test) ✗ go test -coverprofile=/tmp/coverage.out INFO[0000] visited count=1 module=main name=zouying PASS coverage: 62.5% of statements ok _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test 0.015s ➜ how_to_test git:(how_to_test) ✗ go tool cover -html=/tmp/coverage.out

效果图为：

绿色的表示测试代码覆盖住的，红色的表示没有覆盖。

第一个测试用例是直接测试http处理函数，我们使用了httptest.NewRecorder()创建ResponseRecorder对象，其中实现了 ResponseWriter interface。该对象在内存中记录了http response的状态。

还有一种测试方法是运行一个HTTP Server，使用HTTP Client请求该Server对应的接口。

httptest package中提供了NewServer方法，监听HandlerFunc处理函数，启动Server，启动Server的地址通过URL成员获得，例如：http://127.0.0.1:52412。需要注意的是，使用完毕后记得调用关闭：Close()。

代码如下，

func TestHTTPServer(t *testing.T) {
	ts := httptest.NewServer(http.HandlerFunc(handleHello))
	defer ts.Close()

	logrus.Infof("server url: %s", ts.URL)

	testURL := ts.URL + "/hello?name=zouying"
	resp, err := http.Get(testURL)
	if err != nil {
		t.Error(err)
		return
	}
	if g, w := resp.StatusCode, http.StatusOK; g != w {
		t.Errorf("status code = %q; want %q", g, w)
		return
	}
}

运行测试，

➜  how_to_test git:(master) ✗ go test -v -run=TestHTTPServer
=== RUN   TestHTTPServer
INFO[0000] server url: http://127.0.0.1:52506
INFO[0000] visited                                       count=1 module=main name=zouying
--- PASS: TestHTTPServer (0.00s)
PASS
ok      _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test      0.015s

测试技巧：表格测试 (Table Based Tests)

代码如下，

func TestHelloHandlerMultiple(t *testing.T) {
	tests := []struct {
		name string
		wCnt int
	}{
		{name: "zouying", wCnt: 1},
		{name: "zouying", wCnt: 2},
		{name: "user2", wCnt: 1},
		{name: "user3", wCnt: 1},
	}

	for _, tc := range tests {
		rw := httptest.NewRecorder()
		req := httptest.NewRequest(http.MethodPost, "/hello?name="+tc.name, nil)
		handleHello(rw, req)

		if rw.Code != http.StatusOK {
			t.Errorf("status code not ok, status code is %v", rw.Code)
		}

		if counter[tc.name] != tc.wCnt {
			t.Errorf("counter value is error: visitor=%s count=%v", tc.name, counter[tc.name])
		}
	}
}

运行测试，

➜  how_to_test git:(how_to_test) ✗ go test -run=TestHelloHandlerMultiple
INFO[0000] visited                                       count=1 module=main name=zouying
INFO[0000] visited                                       count=2 module=main name=zouying
INFO[0000] visited                                       count=1 module=main name=user2
INFO[0000] visited                                       count=1 module=main name=user3
PASS
ok      _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test      0.016s

测试工具：testify

使用工具介绍各种 if {}判断，产生大量的冗余代码。

代码，

func TestHelloHandlerMultipleWithAssert(t *testing.T) {

	tests := []struct {
		name string
		wCnt int
	}{
		{name: "zouying", wCnt: 1},
		{name: "zouying", wCnt: 2},
		{name: "user2", wCnt: 1},
		{name: "user3", wCnt: 1},
	}

	for _, tc := range tests {
		rw := httptest.NewRecorder()
		req := httptest.NewRequest(http.MethodPost, "/hello?name="+tc.name, nil)
		handleHello(rw, req)

		assert.Equal(t, http.StatusOK, rw.Code)
		assert.Equal(t, tc.wCnt, counter[tc.name])
	}
}

Sub Test

func TestHelloHandlerInSubtest(t *testing.T) {

	tests := []struct {
		name string
		wCnt int
	}{
		{name: "zouying", wCnt: 1},
		{name: "user2", wCnt: 1},
		{name: "user3", wCnt: 1},
	}

	for _, tc := range tests {
		t.Run("test-"+tc.name, func(t *testing.T) {
			rw := httptest.NewRecorder()
			req := httptest.NewRequest(http.MethodPost, "/hello?name="+tc.name, nil)
			handleHello(rw, req)

			assert.Equal(t, http.StatusOK, rw.Code)
			assert.Equal(t, tc.wCnt, counter[tc.name])
		})
	}
}

运行测试，

➜  how_to_test git:(how_to_test) ✗ go test -v . -run=TestHelloHandlerInSubtest
=== RUN   TestHelloHandlerInSubtest
=== RUN   TestHelloHandlerInSubtest/test-zouying
time="2018-12-23T23:07:19+08:00" level=info msg=visited count=1 module=main name=zouying
=== RUN   TestHelloHandlerInSubtest/test-user2
time="2018-12-23T23:07:19+08:00" level=info msg=visited count=1 module=main name=user2
=== RUN   TestHelloHandlerInSubtest/test-user3
time="2018-12-23T23:07:19+08:00" level=info msg=visited count=1 module=main name=user3
--- PASS: TestHelloHandlerInSubtest (0.00s)
    --- PASS: TestHelloHandlerInSubtest/test-zouying (0.00s)
    --- PASS: TestHelloHandlerInSubtest/test-user2 (0.00s)
    --- PASS: TestHelloHandlerInSubtest/test-user3 (0.00s)
PASS
ok      _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test      0.016s

Data Race Detect

多个goroutine同时访问共享数据时，如果数据不是线程安全的，那么有可能会产生data race。

HOW TO

go test -race

测试代码

func TestHelloHandlerDetectDataRace(t *testing.T) {

	tests := []struct {
		name string
		wCnt int
	}{
		{name: "zouying", wCnt: 1},
		{name: "zouying", wCnt: 2},
		{name: "user2", wCnt: 1},
		{name: "user3", wCnt: 1},
	}

	for _, tc := range tests {
		rw := httptest.NewRecorder()
		req := httptest.NewRequest(http.MethodPost, "/hello?name="+tc.name, nil)
		handleHello(rw, req)

		assert.Equal(t, http.StatusOK, rw.Code)
		assert.Equal(t, tc.wCnt, counter[tc.name])
	}
}

运行测试

➜  how_to_test git:(how_to_test) ✗ go test -race -v . -run=TestHelloHandlerDetectDataRace
=== RUN   TestHelloHandlerDetectDataRace
time="2018-12-23T22:58:22+08:00" level=info msg=visited count=1 module=main name=zouying
time="2018-12-23T22:58:22+08:00" level=info msg=visited count=2 module=main name=zouying
time="2018-12-23T22:58:22+08:00" level=info msg=visited count=1 module=main name=user2
time="2018-12-23T22:58:22+08:00" level=info msg=visited count=1 module=main name=user3
--- PASS: TestHelloHandlerDetectDataRace (0.00s)
PASS
ok      _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test      1.029s

测试通过，是否证明了我们的代码是没有问题的呢？

其实并非如此，只是没有检测出来。为什么没有检测出来？

是因为没有多个goroutine同时运行，访问共同的数据。

修改代码

func TestHelloHandlerDetectDataRace(t *testing.T) {

	tests := []struct {
		name string
		wCnt int
	}{
		{name: "zouying", wCnt: 1},
		{name: "user2", wCnt: 1},
		{name: "user3", wCnt: 1},
	}

	var wg sync.WaitGroup
	wg.Add(len(tests))
	for _, tc := range tests {
		name := tc.name
		want := tc.wCnt

		go func() {
			defer wg.Done()

			rw := httptest.NewRecorder()
			req := httptest.NewRequest(http.MethodPost, "/hello?name="+name, nil)
			handleHello(rw, req)

			assert.Equal(t, http.StatusOK, rw.Code)
			assert.Equal(t, want, counter[name])
		}()
	}
	wg.Wait()
}

运行测试

➜  how_to_test git:(how_to_test) ✗ go test -race . -run=TestHelloHandlerDetectDataRace
==================
WARNING: DATA RACE
Write at 0x00c0000a8f90 by goroutine 8:
  runtime.mapassign_faststr()
      /usr/local/go/src/runtime/map_faststr.go:190 +0x0
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.handleHello()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main.go:14 +0x11c
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace.func1()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:144 +0x211

Previous read at 0x00c0000a8f90 by goroutine 7:
  runtime.mapaccess1_faststr()
      /usr/local/go/src/runtime/map_faststr.go:12 +0x0
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.handleHello()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main.go:14 +0xbc
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace.func1()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:144 +0x211

Goroutine 8 (running) created at:
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:139 +0x154
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162

Goroutine 7 (running) created at:
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:139 +0x154
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162
==================
==================
WARNING: DATA RACE
Read at 0x00c0000a8f90 by goroutine 9:
  runtime.mapaccess1_faststr()
      /usr/local/go/src/runtime/map_faststr.go:12 +0x0
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.handleHello()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main.go:14 +0xbc
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace.func1()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:144 +0x211

Previous write at 0x00c0000a8f90 by goroutine 8:
  runtime.mapassign_faststr()
      /usr/local/go/src/runtime/map_faststr.go:190 +0x0
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.handleHello()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main.go:14 +0x11c
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace.func1()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:144 +0x211

Goroutine 9 (running) created at:
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:139 +0x154
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162

Goroutine 8 (running) created at:
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:139 +0x154
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162
==================
==================
WARNING: DATA RACE
Write at 0x00c0000a8f90 by goroutine 7:
  runtime.mapassign_faststr()
      /usr/local/go/src/runtime/map_faststr.go:190 +0x0
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.handleHello()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main.go:14 +0x11c
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace.func1()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:144 +0x211

Previous write at 0x00c0000a8f90 by goroutine 8:
  runtime.mapassign_faststr()
      /usr/local/go/src/runtime/map_faststr.go:190 +0x0
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.handleHello()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main.go:14 +0x11c
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace.func1()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:144 +0x211

Goroutine 7 (running) created at:
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:139 +0x154
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162

Goroutine 8 (running) created at:
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:139 +0x154
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162
==================
time="2018-12-23T23:13:06+08:00" level=info msg=visited count=1 module=main name=user2
time="2018-12-23T23:13:06+08:00" level=info msg=visited count=1 module=main name=user3
time="2018-12-23T23:13:06+08:00" level=info msg=visited count=1 module=main name=zouying
--- FAIL: TestHelloHandlerDetectDataRace (0.00s)
    testing.go:771: race detected during execution of test
FAIL
FAIL    _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test      0.030s

分析报错

==================
WARNING: DATA RACE
Write at 0x00c0000a8f90 by goroutine 8:
  runtime.mapassign_faststr()
      /usr/local/go/src/runtime/map_faststr.go:190 +0x0
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.handleHello()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main.go:14 +0x11c
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace.func1()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:144 +0x211

Previous read at 0x00c0000a8f90 by goroutine 7:
  runtime.mapaccess1_faststr()
      /usr/local/go/src/runtime/map_faststr.go:12 +0x0
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.handleHello()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main.go:14 +0xbc
  _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test.TestHelloHandlerDetectDataRace.func1()
      /Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test/main_test.go:144 +0x211

goroutine 8, goroutine 7, ...
DATA RACE
how_to_test/main.go:14：counter[name]++
runtime/map_faststr.go:190

原因是因为在多个goroutine中，对map同时进行了++操作，而在go中，map又不是线程安全的（线程安全的map参考sync包中的map），需要进行保护。

修复race

如果咱们的代码中有data race，那么一般使用下面方式可以避免，

使用channel。

Share Memory By Communicating

Go by Example: Channels

messages := make(chan string, 2)

messages <- "buffered"
messages <- "channel"

使用mutex。

使用atomic。

Go by Example: Atomic Counters

import "sync/atomic"

var ops uint64

for i := 0; i < 50; i++ {
    go func() {
        for {
            atomic.AddUint64(&ops, 1)
        }
    }()
}

opsFinal := atomic.LoadUint64(&ops)

sync/atomic package

引入mutex解决问题

增加var mu sync.Mutex对counter map进行保护。
在对counter访问前进行Lock操作，访问结束后，进行Unlock操作。

修改代码为，

package main

import (
	"fmt"
	"net/http"
	"sync"

	"github.com/sirupsen/logrus"
)

var counter = map[string]int{}
var mu sync.Mutex // mutex for counter

func handleHello(w http.ResponseWriter, r *http.Request) {
	name := r.FormValue("name")
	mu.Lock()
	counter[name]++
	cnt := counter[name]
	mu.Unlock()

	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	w.Write([]byte("<h1 style='color: " + r.FormValue("color") +
		"'>Welcome!</h1> <p>Name: " + name + "</p> <p>Count: " + fmt.Sprint(cnt) + "</p>"))

	logrus.WithFields(logrus.Fields{
		"module": "main",
		"name":   name,
		"count":  cnt,
	}).Infof("visited")
}

func main() {
	logrus.SetFormatter(&logrus.JSONFormatter{})

	http.HandleFunc("/hello", handleHello)
	logrus.Fatal(http.ListenAndServe(":8080", nil))
}

测试代码，

➜  how_to_test git:(how_to_test) ✗ go test -v -race . -run=TestHelloHandlerDetectDataRace
=== RUN   TestHelloHandlerDetectDataRace
time="2018-12-24T10:11:23+08:00" level=info msg=visited count=1 module=main name=user3
time="2018-12-24T10:11:23+08:00" level=info msg=visited count=1 module=main name=zouying
time="2018-12-24T10:11:23+08:00" level=info msg=visited count=1 module=main name=user2
--- PASS: TestHelloHandlerDetectDataRace (0.00s)
PASS
ok      _/Users/zouying/src/Github.com/ZOUYING/learning_golang/how_to_test      1.025s

具体参考：

https://golang.org/pkg/testing/

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