unit-testing - 如何对 Go Gin 处理程序函数进行单元测试？

Question

我有这样的 Controller 功能....

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 Struct 是这样的..

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"`
}

我的测试功能是这样的..

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

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]

但是当我在我的 Controller 函数中注释掉 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？

Answer 1

要测试涉及 HTTP 请求的操作，您必须实际初始化 *http.Request并将其设置为 Gin 上下文。专门测试c.BindQuery正确初始化请求的 URL 就足够了和 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(bind)，请参阅 this answer .

服务电话 services.WeldprogService.GetMaterialByFilter(&queryParam)不能按原样测试。为了可测试，它必须(理想情况下)是一个接口(interface)，并以某种方式作为处理程序的依赖项注入(inject)。
假设它已经是一个接口(interface)，要使其可注入(inject)，您要么需要它作为处理程序参数——但这会迫使你更改处理程序的签名——或者将其设置为 Gin 上下文值:

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:

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)
    // ... 
}