在 Golang 中制作模拟 gin.Context
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)
}
*/
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()
}
}