3_test.md

marp
true

Golang Tutorial #3

• unit test
• benchmark
• debug on vscode

---

unit test tool

• assert
• dockertest
• gock

---

unit test flow control

// init_test.go
func TestMain(m *testing.M) {
	log.SetOutput(os.Stdout)
	log.SetFlags(log.LstdFlags)
	var p *int
	retCode := 0
	p = &retCode
	BeforeTest()
	defer AfterTest(p)
	*p = m.Run()
}

---

Assert

func TestGetMongoDBInfo(t *testing.T) {
	mongoConfig := getMongoDBInfo()
	assert.Equal(t, "testt", mongoConfig.Name)
}

--- FAIL: TestGetMongoDBInfo (0.00s)
    .../main_test.go:54:
        	Error Trace:	main_test.go:54
        	Error:      	Not equal:
        	            	expected: "testt"
        	            	actual  : "test"
        	Test:       	TestGetMongoDBInfo
FAIL

---

HTTP mock

defer gock.Off() // Flush pending mocks after test execution
gock.InterceptClient(httpClient)
defer gock.RestoreClient(httpClient)
apDomain := "http://test.com"
path := "/test"
gock.New(apDomain).
    Get(path).
    Reply(200).
    JSON(map[string]string{
        "id": "123",
    })

---

static function mock

var (
	getProvisionFunc = provision.GetProvision
)

// test
	getProvisionFunc = func(ctx goctx.Context, service string, rp *redispool.Pool) (bool, gopkg.CodeError) {
		if service == "bad" {
			return false, nil
		}
		return true, nil
	}

---

dockertest run mongo

var (
	dockerPool     *dockertest.Pool
	dockerResource *dockertest.Resource
)

dockerPool, err = dockertest.NewPool("")
dockerResource, err = dockerPool.Run("mongo", "3.4", nil)
dockerResource.GetPort("27017/tcp")

---

dockertest teardown

func AfterTest(ret *int) {
	if e := recover(); e != nil {
		dockerPool.Purge(dockerResource)
		os.Exit(1)
	}
	dockerPool.Purge(dockerResource)
	os.Exit(*ret)
}

• sometimes teardown fail, please use docker system prune -a

---

go benchmark #1

• go test -benchmem -run=xxx (test cpu time and memory alloc)
• used when compared two or more syntax/function

func BenchmarkIfLt1(b *testing.B) {
	count := 0
	test := ""
	for n := 0; n < b.N; n++ {
		if len(test) < 1 {
			count++
		}
	}
	fmt.Println("lt1:", count)
}

---

go benchmark result

BenchmarkIfLt1-4   	lt1: 100
lt1: 10000
lt1: 1000000
lt1: 100000000
lt1: 2000000000
2000000000	         0.64 ns/op	       0 B/op	       0 allocs/op
}

---

go debug on vscode

• update go tools of vscode
• go get -u github.com/go-delve/delve/cmd/dlv make sure delve version support go version
• lazy: open main.go and launch debugger
• check your debugger launch point must in main package
• all check point could be debugged

---

go profiling

• https://github.com/davecheney/gophercon2018-performance-tuning-workshop
• go tool pprof
• http pprof
• go tool pprof -http=":8011" http://localhost:10201/debug/pprof/profile?seconds=30

---

HTTP pprof example

import (
	"log"
	"net/http"
	_ "net/http/pprof"
)

// ActivateProfile runs the profiling endpoint
func ActivateProfile() {
	log.Println("Start profiling")
	go http.ListenAndServe(":10201", http.DefaultServeMux)
}