我可以使用嵌套接口模拟库代码吗？

Question

我试图在我的 go 代码中的测试中模拟第三方库。但我无法编译我所采取的方法。有什么方法可以使这项工作有效，或者如果我想模拟 的结果，我可以采取另一种方法T2.M2？package mainimport (    "fmt")// Two types in a library that I dont have control overtype T1 struct {}func (T1) M1() T2 {    return T2{}}type T2 struct {}func (T2) M2() {    fmt.Println("hello world")}// I created these interfaces in order to assign an instance of T1 // to a variable of type I1 so that I can mock the behavior of T2.M2()// problem is that this doesn't compile.type I1 interface {    M1() I2}type I2 interface {    M2() // I want to mock this method}// Then I would be able to create a mocktype Mock1 struct {}func (Mock1) M1() I2 {    return Mock2{}}type Mock2 struct {}func (Mock2) M2() {    fmt.Println("HELLO WORLD")}func main() {    var i1 I1    i1 = T1{}    i1.M1().M2()    i1 = Mock1{}    i1.M1().M2()}https://play.golang.org/p/sv-Uuuke1dr

Answer 1

将您的依赖项包装在嵌入依赖类型的结构中：

// answer wrap your dependency

type Ta1 struct {

  T1

}

func (Ta1) M1() I2 {

    return Ta2{}

}

type Ta2 struct {

   T2

}

然后它将起作用：

func main() {

    var i1 I1

    i1 = Ta1{}

    i1.M1().M2()

    i1 = Mock1{}

    i1.M1().M2()

}

尝试一下https://play.golang.org/p/aHr78dY_c9a

Answer 2

你不能在 Go 中模拟结构。只有接口。