ConstructorExample1.swift

protocol Service_A {
    func doSomething()
}

protocol Service_B {
    func doSomething()
}

protocol Service_C {
    func doSomething()
}

protocol Service_D {
    func doSomething()
}

class ViewController_A : ViewController {
    let serviceA: Service_A
    let serviceB: Service_B
    let serviceC: Service_C
    let serviceD: Service_D

    init(
        serviceA: Service_A,
        serviceB: Service_B,
        serviceC: Service_C,
        serviceD: Service_D
        ) {
        self.serviceA = serviceA
        self.serviceB = serviceB
        self.serviceC = serviceC
        self.serviceD = serviceD
        super.init()
    }

    func showNestedViewController() {
        serviceA.doSomething()
        presentViewController(
            ViewController_B(
                serviceB: serviceB,
                serviceC: serviceC,
                serviceD: serviceD
            ),
            animated: true,
            completion: nil
        )
    }
}

// Test code:
let testedVC = ViewController_A(serviceA: TestingServiceA(), serviceB: DummyServiceB(), 
                                serviceC: DummyServiceC(), serviceD: DummyServiceD())
/// now test testedVC for serviceA functionality ...