英文:
Gomock cannot use type map[string]*mockFoo as map[string]foo
问题
我正在使用gomock，并且我有这段示例代码需要进行测试。
type StructA struct {
client map[string]Foo
}
type Foo interface {
methodFoo() string
}
func (a *StructA) MethodA(name string) string {
client := a.client[name]
return client.methodFoo()
}
在我的测试中，我已经为Foo生成了一个名为mockFoo的模拟对象。我使用mockgen v1.6.0生成了Foo接口的模拟对象。
我的测试代码如下：
func Test_MethodA(t *testing.T) {
type fields struct {
client map[string]*mockFoo
}
tests := []struct {
fields fields
want string
}{
// 测试用例
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
a := &StructA{
client: tt.fields.client // 这里有一个错误，提示不能将map[string]*mockFoo作为map[string]Foo类型使用
}
...
})
}
}
简而言之，map[string]*mockFoo不能作为类型map[string]Foo使用。
var foo1 Foo
var mockFoo1 *mockFoo
foo1 = mockFoo1 // 没问题
var fooMap map[string]Foo
var mockFooMap map[string]*mockFoo
fooMap = mockFooMap // 有问题
请问我在这里做错了什么，还是这是预期的行为？谢谢。
英文:
I am using gomock, and I have this piece of example code that I wish to test.
type StructA struct {
client map[string]Foo
}
type Foo interface {
foo.methodFoo() string
}
func (a *structA) MethodA(name string) string {
client := a.client[name]
return client.methodFoo()
}
In my test, i've generated a mock for foo, called mockFoo. Used mockgen v1.6.0 to generate the mock for interface foo.
I have the test code as:
func Test_MethodA(t *testing.T) {
type fields struct {
client map[string]*mockFoo
}
tests := []struct {
fields fields
want string
}
{
// test cases
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
a := &StructA {
client: tt.fields.client //this has an error, saying that we cannot use map[string]*mockFoo as the type map[string]foo
}
...
})
}
}
TLDR is that map[string]*mockFoo cannot be used as the type map[string]Foo.
var foo1 Foo
var mockFoo1 *mockFoo
foo1 = mockFoo1 // no problem
var fooMap map[string]Foo
var mockFooMap map[string]*mockFoo
fooMap = mockFooMap // problematic
May I know if I'm doing anything wrong here or if this an expected behaviour? Thanks.
答案1
得分: 2
根据你的描述，Foo 是一个接口，*mockFoo 实现了 Foo 接口。因此，每当需要一个 Foo 时，你可以使用 *mockFoo。
类型 map[string]Foo 和类型 map[string]*mockFoo 是不同的。它们都是具体类型（不是接口），所以不能互相替换。
不过，你可以使用 map[string]Foo，并将 *mockFoo 的值放入该映射中。根据你的代码，这似乎是你应该做的。声明映射为 map[string]Foo，并在其中使用 *mockFoo 的值。如果你需要将映射的值作为 *mockFoo 引用，你可以使用类型断言来获取 *mockFoo 的值，例如：
fooMap := map[string]Foo{}
fooMap["key"] = mockFoo1
...
value := fooMap["key"].(*mockFoo)
英文:
Based on your description, Foo is an interface, and *mockFoo implements the Foo interface. Thus, whenever a Foo is required, you can used *mockFoo.
The type map[string]Foo is not the same as the type map[string]*mockFoo. Both are concrete types (they are not interfaces), so you cannot substitute one for the other.
You can, however, use map[string]Foo, and put *mockFoo values into that map, and as far as I can see from your code, that's what you should do. Declare the map as map[string]Foo, and use *mockFoo values in it. If you need to refer to the values of the map as *mockFoo, you can type-assert the map value to get the *mockFoo value, that is:
fooMap=map[string]Foo{}
fooMap["key"]=mockFoo1
...
value:=foomap["key"].(*mockFoo)
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