Go language unit test simulates service request and interface return

Catalog

Preface

httptest

gock

install

Examples of use

summary

Preface

This is a Go Unit testing from getting started to quitting the tutorial series 1 piece , How to use httptest and gock Tools for network testing .

In the last article 《Go Unit testing goes from getting started to giving up —0. Unit test basis 》 in , We introduced Go The basic content of language writing unit test .

However, the business scenarios in actual work are often complex , Whether our code is as server Or do we rely on other people to provide network services （ Call someone else's API Interface ） Scene , We usually don't want to really establish a network connection during the test process . This article specifically introduces how to mock Network testing .

httptest

stay Web Unit tests in development scenarios , If it involves HTTP Request recommendation Go Standard library  net/http/httptest  To test , It can significantly improve the testing efficiency .

In this section , We use the common gin Framework for example , Show me how to http server Write unit tests .

Suppose our business logic is to build a http server End , External provision HTTP service . We wrote a helloHandler function , Used to process user requests .

// gin.gopackage httptest_demoimport ( "fmt" "net/http" "github.com/gin-gonic/gin")// Param  Request parameters type Param struct { Name string `json:"name"`}// helloHandler /hello Request handling function func helloHandler(c *gin.Context) { var p Param if err := c.ShouldBindJSON(&p); err != nil {  c.JSON(http.StatusOK, gin.H{   "msg": "we need a name",  })  return } c.JSON(http.StatusOK, gin.H{  "msg": fmt.Sprintf("hello %s", p.Name), })}// SetupRouter  route func SetupRouter() *gin.Engine { router := gin.Default() router.POST("/hello", helloHandler) return router}

Now we need to helloHandler Function writing unit test , In this case, we can use httptest This tool mock One HTTP Request and response recorder , Let's have server The client receives and processes us mock Of HTTP request , At the same time, the response recorder is used to record server The response content returned by the client .

The example code of unit test is as follows ：

// gin_test.gopackage httptest_demoimport ( "encoding/json" "net/http" "net/http/httptest" "strings" "testing" "github.com/stretchr/testify/assert")func Test_helloHandler(t *testing.T) { //  Define two test cases  tests := []struct {  name   string  param  string  expect string }{  {"base case", `{"name": "liwenzhou"}`, "hello liwenzhou"},  {"bad case", "", "we need a name"}, } r := SetupRouter() for _, tt := range tests {  t.Run(tt.name, func(t *testing.T) {   // mock One HTTP request    req := httptest.NewRequest(    "POST",                      //  Request method     "/hello",                    //  request URL    strings.NewReader(tt.param), //  Request parameters    )   // mock A response recorder    w := httptest.NewRecorder()   //  Give Way server End treatment mock Request and record the returned response content    r.ServeHTTP(w, req)   //  Verify whether the status code meets the expectation    assert.Equal(t, http.StatusOK, w.Code)   //  Parse and verify whether the response content is compound with the expectation    var resp map[string]string   err := json.Unmarshal([]byte(w.Body.String()), &resp)   assert.Nil(t, err)   assert.Equal(t, tt.expect, resp["msg"])  }) }}

Perform unit tests , Check the test results

* go test -v
=== RUN   Test_helloHandler
[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.
[GIN-debug] [WARNING] Running in "debug" mode. Switch to "release" mode in production.
 - using env:   export GIN_MODE=release
 - using code:  gin.SetMode(gin.ReleaseMode)
[GIN-debug] POST   /hello                    --> golang-unit-test-demo/httptest_demo.helloHandler (3 handlers)
=== RUN   Test_helloHandler/base_case
[GIN] 2021/09/14 - 22:00:04 | 200 |     164.839µs |       192.0.2.1 | POST     "/hello"
=== RUN   Test_helloHandler/bad_case
[GIN] 2021/09/14 - 22:00:04 | 200 |      23.723µs |       192.0.2.1 | POST     "/hello"
--- PASS: Test_helloHandler (0.00s)
    --- PASS: Test_helloHandler/base_case (0.00s)
    --- PASS: Test_helloHandler/bad_case (0.00s)
PASS
ok      golang-unit-test-demo/httptest_demo     0.055s

Through this example, we have mastered how to use httptest stay HTTP Server Unit tests are written for the request handling function in the service .

gock

The above example shows how to do this in HTTP Server Write unit tests for request handling functions in the service class scenario , So if we are requesting an external in code API Scene （ Such as through API Call other services to get the return value ） How to write unit tests ？

for example , We have the following business logic code , Rely on the outside API：http://your-api.com/post Data provided .

// api.go// ReqParam API Request parameters type ReqParam struct { X int `json:"x"`}// Result API Return results type Result struct { Value int `json:"value"`}func GetResultByAPI(x, y int) int { p := &ReqParam{X: x} b, _ := json.Marshal(p) //  Calling other services API resp, err := http.Post(  "http://your-api.com/post",  "application/json",  bytes.NewBuffer(b), ) if err != nil {  return -1 } body, _ := ioutil.ReadAll(resp.Body) var ret Result if err := json.Unmarshal(body, &ret); err != nil {  return -1 } //  This is right API Do some logic processing on the returned data  return ret.Value + y}

When writing unit tests for business code like the above , If you don't really want to send requests during the testing process or the dependent external interface has not been developed yet , In unit tests, we can test the dependent API Conduct mock.

It is recommended to use gock This library .

install go get -u gopkg.in/h2non/gock.v1 Examples of use

Use gock To the outside API Conduct mock, namely mock Specify the parameters to return the agreed response content . In the following code mock Two sets of data , Two test cases are composed .

// api_test.gopackage gock_demoimport ( "testing" "github.com/stretchr/testify/assert" "gopkg.in/h2non/gock.v1")func TestGetResultByAPI(t *testing.T) { defer gock.Off() //  Refresh pending after test execution mock // mock  Ask outside api Shi Chuanshen x=1 return 100 gock.New("http://your-api.com").  Post("/post").  MatchType("json").  JSON(map[string]int{"x": 1}).  Reply(200).  JSON(map[string]int{"value": 100}) //  Call our business function  res := GetResultByAPI(1, 1) //  Verify whether the returned result meets the expectation  assert.Equal(t, res, 101) // mock  Ask outside api Shi Chuanshen x=2 return 200 gock.New("http://your-api.com").  Post("/post").  MatchType("json").  JSON(map[string]int{"x": 2}).  Reply(200).  JSON(map[string]int{"value": 200}) //  Call our business function  res = GetResultByAPI(2, 2) //  Verify whether the returned result meets the expectation  assert.Equal(t, res, 202) assert.True(t, gock.IsDone()) //  Assertion mock Be triggered }

Execute the unit tests written above , Look at the test results .

* go test -v
=== RUN   TestGetResultByAPI
--- PASS: TestGetResultByAPI (0.00s)
PASS
ok      golang-unit-test-demo/gock_demo 0.054s

The test results are in perfect agreement with the expectations .

In this example , In order to let everyone know clearly gock Use , I deliberately did not use table driven testing . Leave a little homework for everyone ： Rewrite this unit test into a table driven test style by yourself , As a review and test of the last two tutorials .

​ Here the webmaster comes to represent the class , You can send this assignment to me by private mail on the official account , Let's exchange the answers . If you want to fish, you can ask me for the answer directly , But don't go whoring for nothing , There must be a third company ：）.

summary

How to deal with external dependencies when writing unit tests for code in daily work development is the most common problem , This article explains how to use it httptest and gock Tools mock Related dependencies .

Later we will go further , Details on dependencies MySQL and Redis The scenario of how to write unit tests , More about Go For information about unit test simulation service request and interface return, please pay attention to other relevant articles on Sdn ！