ConformanceLocked

public protocol ConformanceLocked

Protocols that inherit this protocol are considered locked and can be conformed to and implemented only inside the TomTomSDK.

// An example of protocol that provides necessary functionality in the TomTomSDK.
public protocol Planner: ConformanceLocked {
    func plan()
}

// An abstraction from the client side that provides the same interface but is not locked.
// Every TomTomSDK protocol might need this protocol clone.
// Use this type to pass it in the application and in tests.
protocol ClientPlanner {
   // The method should have the same signature
   func plan()
}

// Wrapper implementation on the client side that will contain TomTomSDK dependency
// but conform to the non-locked protocol
class ClientWrapperPlanner: ClientPlanner {
    let planner: Planner
    init(_ planner: Planner) {
        self.planner = planner
    }

    func plan() {
        planner.plan()
    }
}

// An example of the production code that needs to be tested.
// Use `ClientPlanner` in your production code, so you can mock it.
struct PlannerViewModel {
   init(_ planner: ClientPlanner) { }
   //
   // ...
}

// In production code
let planner: Planner = ... // getting real planner
PlannerViewModel(ClientWrapperPlanner(planner))

By depending on `ClientPlanner` a `PlannerViewModel` instance can be tested
by mocking all its dependencies. To mock its dependencies, replace `ClientWrapperPlanner` with a
mocked implementation of `ClientPlanner`.