在 Golang 中制作模拟 gin.Context [英] Make mock gin.Context in Golang

问题描述

我正在使用 Gin 框架编写 REST API.但是我在测试控制器和研究 TDD 和 Mock 时遇到了麻烦.我尝试将 TDD 和 Mock 应用于我的代码，但我不能.

I'm writing a REST API using Gin framework. But I was faced a trouble testing my controllers and researching TDD and Mock. I tried to apply TDD and Mock to my code but I could not.

我创建了一个非常精简的测试环境并尝试创建一个控制器测试.如何为 Gin.Context 创建 Mock?

I created a very reduced test environment and tried to create a controller test. How do I create a Mock for Gin.Context?

这是我的示例代码:

package main

import (
    "strconv"
    "github.com/gin-gonic/gin"
)

// MODELS
type Users []User
type User struct {
    Name string `json"name"`
}


func main() {
    r := gin.Default()

    r.GET("/users", GetUsers)
    r.GET("/users/:id", GetUser)

    r.Run(":8080")
}

// ROUTES
func GetUsers(c *gin.Context) {
    repo := UserRepository{}
    ctrl := UserController{}

    ctrl.GetAll(c, repo)
}

func GetUser(c *gin.Context) {
    repo := UserRepository{}
    ctrl := UserController{}

    ctrl.Get(c, repo)
}

// CONTROLLER
type UserController struct{}

func (ctrl UserController) GetAll(c *gin.Context, repository UserRepositoryIterface) {
    c.JSON(200, repository.GetAll())
}

func (ctrl UserController) Get(c *gin.Context, repository UserRepositoryIterface) {

    id := c.Param("id")

    idConv, _ := strconv.Atoi(id)

    c.JSON(200, repository.Get(idConv))
}

// REPOSITORY
type UserRepository struct{}
type UserRepositoryIterface interface {
    GetAll() Users
    Get(id int) User
}

func (r UserRepository) GetAll() Users {
    users := Users{
        {Name : "Wilson"},
        {Name : "Panda"},
    }

    return users
}

func (r UserRepository) Get(id int) User {
    users := Users{
        {Name : "Wilson"},
        {Name : "Panda"},
    }

    return users[id-1]
}

我的测试示例:

package main

import(
    "testing"
    _ "github.com/gin-gonic/gin"
)

type UserRepositoryMock struct{}

func (r UserRepositoryMock) GetAll() Users {
    users := Users{
        {Name : "Wilson"},
        {Name : "Panda"},
    }

    return users
}

func (r UserRepositoryMock) Get(id int) User {
    users := Users{
        {Name : "Wilson"},
        {Name : "Panda"},
    }

    return users[id-1]
}


// TESTING REPOSITORY FUNCTIONS
func TestRepoGetAll(t *testing.T) {

    userRepo := UserRepository{}

    amountUsers := len(userRepo.GetAll())

    if amountUsers != 2 {
        t.Errorf("Esperado %d, recebido %d", 2, amountUsers)
    }
}

func TestRepoGet(t *testing.T) {

    expectedUser := struct{
        Name string
    }{
        "Wilson",
    }

    userRepo := UserRepository{}

    user := userRepo.Get(1)

    if user.Name != expectedUser.Name {
        t.Errorf("Esperado %s, recebido %s", expectedUser.Name, user.Name)
    }
}

/* HOW TO TEST CONTROLLER?
func TestControllerGetAll(t *testing.T) {
    gin.SetMode(gin.TestMode)
    c := &gin.Context{}
    c.Status(200)
    repo := UserRepositoryMock{}
    ctrl := UserController{}

    ctrl.GetAll(c, repo)
}
*/

推荐答案

如果将问题简化为如何为函数参数创建模拟?"答案是:使用接口而不是具体类型.

If to reduce the question to "How to create mock for a function argument?" the answer is: use interfaces not concrete types.

type Context struct 是一个具体的类型文字，Gin 没有提供合适的接口.但是你可以自己声明.由于您仅使用 Context 中的 JSON 方法，因此您可以声明更简单的接口:

type Context struct is a concrete type literal and Gin doesn't provide appropriate interface. But you can declare it by yourself. Since you are using only JSON method from Context you can declare extra-simple interface:

type JSONer interface {
    JSON(code int, obj interface{})
}

并在所有期望 Context 作为参数的函数中使用 JSONer 类型代替 Context 类型:

And use JSONer type instead Context type in all your functions which expect Context as argument:

/* Note, you can't declare argument as a pointer to interface type,
   but when you call it you can pass pointer to type which
   implements the interface.*/
func GetUsers(c JSONer) {
    repo := UserRepository{}
    ctrl := UserController{}

    ctrl.GetAll(c, repo)
}

func GetUser(c JSONer) {
    repo := UserRepository{}
    ctrl := UserController{}

    ctrl.Get(c, repo)
}

func (ctrl UserController) GetAll(c JSONer, repository UserRepositoryIterface) {
    c.JSON(200, repository.GetAll())
}

func (ctrl UserController) Get(c JSONer, repository UserRepositoryIterface) {

    id := c.Param("id")

    idConv, _ := strconv.Atoi(id)

    c.JSON(200, repository.Get(idConv))
}

现在很容易测试

type ContextMock struct {
    JSONCalled bool
}

func (c *ContextMock) JSON(code int, obj interface{}){
    c.JSONCalled = true
}

func TestControllerGetAll(t *testing.T) {
    gin.SetMode(gin.TestMode)
    c := &ContextMock{false}
    c.Status(200)
    repo := UserRepositoryMock{}
    ctrl := UserController{}

    ctrl.GetAll(c, repo)

    if c.JSONCalled == false {
        t.Fail()
    }
}

尽可能简单的例子.

还有一个问题比较贴切

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