go测试注意事项

• go的测试文件需要以_test结尾
• 测试函数名必须以大写Test开头

表格驱动测试

• 分离测试数据和测试逻辑
• 明确的出错信息
• 可以部分失败

func add(a, b int) int {
	return a + b
}

func TestAdd(t *testing.T) {
    var add =func (a, b int) int {
        return a + b
    }

	var tests = []struct {
		a, b, c int
	}{
		{1, 2, 3},
		{1, 5, 6},
		{1, 8, 9},
	}

	for _, tt := range tests {
		if actual := add(tt.a, tt.b); actual != tt.c {
			t.Errorf("add(%d, %d);"+
				"got %d; expected %d", tt.a, tt.b, actual, tt.c)
		}
	}
}

func TestSubstr(t *testing.T) {
	var longestStrInString = func(str string) int {
		var length int = 0
		var start int = 0
		lastOcc := make(map[rune]int)
		for i, char := range []rune(str) {
			if index, ok := lastOcc[char]; ok && index >= start {
				start = i
			}
			if i-start+1 > length {
				length = i - start + 1
			}
			lastOcc[char] = i
		}
		return length
	}

	var tests = []struct {
		a string
		b int
	}{
		{"pwbds6786868767867wbertyuio", 11},
		{"", 0},
		{"这里是你最偶偶的地方", 6},
		{"一二三二一", 3},
	}

	for _, tt := range tests {
		if actual := longestStrInString(tt.a); actual != tt.b {
			t.Errorf("longestStrInString(%s);"+
				"got %d; expected %d", tt.a, actual, tt.b)
		}
	}
}

go测试命令

# 测试当前目录所有test文件
go test .

# 生成test的测试结果文件
go test -coverprofile=c.out

# 查看cover的可用命令
go tool cover

# 使用html的方式展示覆盖率
go tool cover -html=c.out

# 查看_test.go的内容
less _test.go

go benchmark和pprof

// map版本  较短字符串处理速度快
func LongestStrInString(str string) int {
	var length int = 0
	var start int = 0
	lastOcc := make(map[rune]int)
	for i, char := range []rune(str) {
		if index, ok := lastOcc[char]; ok && index >= start {
			start = i
		}
		if i-start+1 > length {
			length = i - start + 1
		}
		lastOcc[char] = i
	}
	return length
}


// slice版本的处理  较长字符串处理速度慢
var lastOcc = make([]int, 0xffff)
func LongestStrInStringUpgrade(str string) int {
	for i := range lastOcc {
		lastOcc[i] = -1
	}
	var length int = 0
	var start int = 0
	for i, char := range []rune(str) {
		if index := lastOcc[char]; index >= start {
			start = i
		}
		if i-start+1 > length {
			length = i - start + 1
		}
		lastOcc[char] = i
	}
	return length
}

// benchmark
func BenchmarkLongestStrInString(b *testing.B) {
	s := "这里是你最偶偶的地方"
	res := 6

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		actual := LongestStrInString(s)
		if actual != res {
			b.Errorf("got %d for input %s, expected %d", actual, s, res)
		}
	}
}

# benchmark测试命令
go test -bench .

# 生成性能报告
go test -bench . -cpuprofile cpu.out

# 交互式命令
go tool pprof cpu.out 
web #显示运行耗时的程序

package main

import (
	"errors"
	"io/ioutil"
	"net/http"
	"net/http/httptest"
	"os"
	"strings"
	"testing"
	"time"
)

func panicError(writer http.ResponseWriter, request *http.Request) error {
	return errors.New("Internal Server Error")
}
func errUserError(writer http.ResponseWriter, request *http.Request) error {
	return custom_error{"user error", time.Now(), "position"}
}

func notExistError(writer http.ResponseWriter, request *http.Request) error {
	return os.ErrNotExist
}

func forbidError(writer http.ResponseWriter, request *http.Request) error {
	return os.ErrPermission
}

func noError(writer http.ResponseWriter, request *http.Request) error {
	return nil
}

var tests = []struct {
	h       appHandler
	code    int
	message string
}{
	{panicError, 500, "Internal Server Error"},
	{errUserError, 400, "position: user error"},
	{notExistError, 404, "Not Found"},
	{forbidError, 403, "Forbidden"},
	{noError, 200, ""},
}

// 使用假的http请求来测试
func TestErrWrapper(t *testing.T) {
	for _, tt := range tests {
		f := errWraper(tt.h)
		response := httptest.NewRecorder()
		request := httptest.NewRequest(
			http.MethodGet,
			"http://www.baidu.com",
			nil,
		)
		f(response, request)
		verifyResponse(response.Result(), tt.code, tt.message, t)
	}
}

// 使用真实的http请求来测试
func TestErrWraperInServer(t *testing.T) {
	for _, tt := range tests {
		f := errWraper(tt.h)
		server := httptest.NewServer(http.HandlerFunc(f))
		resp, _ := http.Get(server.URL)
		verifyResponse(resp, tt.code, tt.message, t)
	}
}

func verifyResponse(resp *http.Response, expectedCode int, expectedMsg string, t *testing.T) {
	b, _ := ioutil.ReadAll(resp.Body)
	body := strings.Trim(string(b), "\n")
	if resp.StatusCode != expectedCode || body != expectedMsg {
		t.Errorf("expect (%d, %s);"+
			"got (%d, %s)",
			expectedCode, expectedMsg,
			resp.StatusCode, body)
	}
}