简介

日常开发中, 测试是不能缺少的.

Go 标准库中有一个叫做 testing 的测试框架, 可以用于单元测试和性能测试.

它是和命令 go test 集成使用的.

测试文件是以后缀 _test.go 命名的, 通常和被测试的文件放在同一个包中.

单元测试

单元测试的格式形如:

func TestAbs(t *testing.T) { got := Abs(-1) if got != 1 { t.Errorf("Abs(-1) = %d; want 1", got) }}

在 util 目录下创建一个文件 util_test.go, 添加一个单元测试:

package utilimport "testing"// 普通的测试func TestGenShortID(t *testing.T) { shortID, err := GenShortID() if shortID == "" || err != nil { t.Error("GenShortID failed") }}

然后, 在根目录下运行 go test -v ./util/, 测试结果如下:

root@592402321ce7:/workspace# go test -v ./util/=== RUN TestGenShortID--- PASS: TestGenShortID (0.00s)PASSok tzh.com/web/util 0.006s

性能测试

性能测试的结果形如:

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

在 util_test.go 添加性能测试:

// 性能测试func BenchmarkGenShortID(b *testing.B) { for i := 0; i < b.N; i++ { GenShortID() }}

运行结果如下(使用 --run=none 避免运行普通的测试函数, 因为一般不可能有函数名匹配 none):

root@592402321ce7:/workspace# go test -v -bench="BenchmarkGenShortID$" --run=none ./util/goos: linuxgoarch: amd64pkg: tzh.com/web/utilBenchmarkGenShortID-2 507237 2352 ns/opPASSok tzh.com/web/util 1.229s

这说明, 平均每次运行 GenShortID() 需要 2352 纳秒.

性能分析

运行测试的时候, 可以指定一些参数, 生成性能文件 profile.

-blockprofile block.out Write a goroutine blocking profile to the specified file when all tests are complete. Writes test binary as -c would.-blockprofilerate n Control the detail provided in goroutine blocking profiles by calling runtime.SetBlockProfileRate with n. See 'go doc runtime.SetBlockProfileRate'. The profiler aims to sample, on average, one blocking event every n nanoseconds the program spends blocked. By default, if -test.blockprofile is set without this flag, all blocking events are recorded, equivalent to -test.blockprofilerate=1.-coverprofile cover.out Write a coverage profile to the file after all tests have passed. Sets -cover.-cpuprofile cpu.out Write a CPU profile to the specified file before exiting. Writes test binary as -c would.-memprofile mem.out Write an allocation profile to the file after all tests have passed. Writes test binary as -c would.-memprofilerate n Enable more precise (and expensive) memory allocation profiles by setting runtime.MemProfileRate. See 'go doc runtime.MemProfileRate'. To profile all memory allocations, use -test.memprofilerate=1.-mutexprofile mutex.out Write a mutex contention profile to the specified file when all tests are complete. Writes test binary as -c would.-mutexprofilefraction n Sample 1 in n stack traces of goroutines holding a contended mutex.

使用下面的命令, 生成 CPU 的 profile:

go test -v -bench="BenchmarkGenShortID$" --run=none -cpuprofile cpu.out ./util/

当前目录下, 应该会生成 cpu.out 文件和 util.test 文件.

使用下面的命令, 观察耗时操作:

# 进入交互模式go tool pprof cpu.outtop

安装 Graphviz 后可以生成可视化的分析图.

apt install graphvizgo tool pprof -http=":" cpu.out

测试覆盖率

root@592402321ce7:/workspace# go test -v -coverprofile=cover.out ./util/=== RUN TestGenShortID--- PASS: TestGenShortID (0.00s)PASScoverage: 9.1% of statementsok tzh.com/web/util 0.005s coverage: 9.1% of statementsroot@592402321ce7:/workspace# go tool cover -func=cover.outtzh.com/web/util/util.go:12: GenShortID 100.0%tzh.com/web/util/util.go:17: GetReqID 0.0%tzh.com/web/util/util.go:22: TimeToStr 0.0%tzh.com/web/util/util.go:30: GetTag 0.0%total: (statements) 9.1%

使用 -coverprofile=cover.out 选项可以统计测试覆盖率.使用 go tool cover -func=cover.out 可以查看更加详细的测试覆盖率结果,
统计每个函数的测试覆盖率.

总结

测试是开发中非常重要的一个环节, 用于保证软件质量, 切不可偷懒.

当前部分的代码

作为版本 v0.15.0

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