Mocking does not work for the `singleton` scope

[VladimirAmiorkov]

Hi, Thanks for all of the work you have been doing with this project. Its very easy to work with and I have not faced any issues I was not able to resolve. But today after upgrading to 2.x.x I am having an issue with my unit tests and mocking singletons.

In version 1.x.x I was making mocks of my singleton declarations by:

1. Inside setUpWithError I would call Container.Registrations.push()
2. Register a new factory of my mock instance
3. Finally inside tearDownWithError I would call Container.Registrations.pop().

This way my singleton DI would be correctly replaced by my mock instances.

Now I switch to latest version (2.1.x) and I am doing the following:

If I have:

extension Container {
    var myString: Factory<String> { Factory(self) { "Initial string" }.singleton }
}

1. Inside setUpWithError I create a new Container.shared instance Container.shared = Container()
2. Register a new factory of my mock instance: Container.shared.myString.scope(.singleton).register { "New string" }

(also tried with Container.shared.testService.register { "New string" }

But after this mock/change if I call Container.shared.myString.callAsFunction() it gives Initial string

I used String to simply the example but the same behavior is observed with any type of object.

I have checked the docs and I see in the mocks section there is:

extension Container {
    static var myService: MyServiceType { MyService() }
}

...
let _ = Container.myService.register { MockService2() }

But the line Container.myService.register does not compile as there is no register on the MyService. In that example myService is just a static var of a type. Or is this custom code that needs to be written, if yes what should it do?

If I make this into a not singleton by removing the .singleton, then all works as expected.

Am I doing something wrong here? Thanks.

[hmlongco]

I think most of this is addressed in 2.1.3. Pushing/popping containers has no effect on singletons, their scope is outside that of a single container.

That said, registering a change on a singleton Factory works as it did before, the assumption being that if you registered it you're expecting it to be used.

See the Testing Singletons section in Testing for more.

[VladimirAmiorkov]

Thank you very much.