如何对 Go Gin 处理函数进行单元测试? [英] How to unit test a Go Gin handler function?

问题描述

我有一个这样的控制器功能......

I have a controller function like this....

func GetMaterialByFilter(c *gin.Context) {

    queryParam := weldprogs.QueryParam{}
    c.BindQuery(&queryParam)
    materialByFilter, getErr := services.WeldprogService.GetMaterialByFilter(&queryParam)
    if getErr != nil {
        //TODO : Handle user creation error
        c.JSON(getErr.Status, getErr)
        return
    }
    c.JSON(http.StatusOK, materialByFilter)

}

QueryParam 结构是这样的..

QueryParam Struct is like this..

type QueryParam struct {
    Basematgroup_id []string `form:"basematgroup_id"`
    License_id      []string `form:"license_id"`
    Diameter_id     []string `form:"diameter_id"`
    Gasgroup_id     []string `form:"gasgroup_id"`
    Wiregroup_id    []string `form:"wiregroup_id"`
    Wiremat_id      []string `form:"wiremat_id"`
}

我的测试函数是这样的..

My test function is like this..

func TestGetMaterialByFilter(t *testing.T) {
    w := httptest.NewRecorder()
    c, _ := gin.CreateTestContext(w)
    GetMaterialByFilter(c)
    assert.Equal(t, 200, w.Code) 

    var got gin.H
    err := json.Unmarshal(w.Body.Bytes(), &got)
    if err != nil {
        t.Fatal(err)
    }
    fmt.Println(got)
    assert.Equal(t, got, got) 
}

在运行此测试时，它给了我以下错误

On running this test it is giving me the following error

panic: runtime error: invalid memory address or nil pointer dereference [recovered]
        panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x97f626]

但是当我注释掉控制器函数中的 c.BindQuery() 行时，它成功地运行了我的测试函数.我在这里做错了什么?我可以以某种方式模拟 c.BindQuery 函数吗?

But when i comment out the c.BindQuery() line in my controller function it successfully run my test function. What i am doing wrong here? can i somehow mock the c.BindQuery function?

推荐答案

要测试涉及 HTTP 请求的操作，您必须实际初始化一个 *http.Request 并将其设置为 Gin 上下文.要专门测试 c.BindQuery，正确初始化请求的 URL 和 URL.RawQuery 就足够了:

To test operations that involve the HTTP request, you have to actually initialize an *http.Request and set it to the Gin context. To specifically test c.BindQuery it's enough to properly initialize the request's URL and URL.RawQuery:

func mockGin() (*gin.Context, *httptest.ResponseRecorder) {
    w := httptest.NewRecorder()
    c, _ := gin.CreateTestContext(w)

    // test request, must instantiate a request first
    req := &http.Request{
        URL:    &url.URL{},
        Header: make(http.Header), // if you need to test headers
    }
    // example: req.Header.Add("Accept", "application/json")

    // request query
    testQuery := weldprogs.QueryParam{/* init fields */}

    q := req.URL.Query()
    for _, s := range testQuery.Basematgroup_id {
        q.Add("basematgroup_id", s)
    }
    // ... repeat for other fields as needed

    // must set this, since under the hood c.BindQuery calls
    // `req.URL.Query()`, which calls `ParseQuery(u.RawQuery)`
    req.URL.RawQuery = q.Encode()
    
    // finally set the request to the gin context
    c.Request = req

    return c, w
}

如果您需要模拟 JSON 绑定，请参阅此答案.

If you need to mock JSON binding, see this answer.

无法按原样测试服务调用 services.WeldprogService.GetMaterialByFilter(&queryParam).为了可测试，它必须(理想情况下)是一个接口，并以某种方式作为处理程序的依赖项注入.

The service call services.WeldprogService.GetMaterialByFilter(&queryParam) can't be tested as is. To be testable it has to be (ideally) an interface and somehow injected as dependency of your handler.

假设它已经是一个接口，要使其可注入，您要么要求将其作为处理程序参数——但这会强制您更改处理程序的签名——或者将其设置为 Gin 上下文值:

Assuming that it is already an interface, to make it injectable, you either require it as an handler argument — but this forces you to change the signature of the handler —, or you set it as a Gin context value:

func GetMaterialByFilter(c *gin.Context) {
    //...
    weldprogService := mustGetService(c)
    materialByFilter, getErr := weldprogService.GetMaterialByFilter(&queryParam)
    // ...
}

func mustGetService(c *gin.Context) services.WeldprogService {
    svc, exists := c.Get("svc_context_key")
    if !exists {
        panic("service was not set")
    }
    return svc.(services.WeldprogService)
}

然后你可以在你的单元测试中模拟它:

Then you can mock it in your unit tests:

type mockSvc struct {
}

// have 'mockSvc' implement the interface 

func TestGetMaterialByFilter(t *testing.T) {
    w := httptest.NewRecorder()
    c, _ := gin.CreateTestContext(w)

    // now you can set mockSvc into the test context
    c.Set("svc_context_key", &mockSvc{})

    GetMaterialByFilter(c)
    // ... 
}

这篇关于如何对 Go Gin 处理函数进行单元测试?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！