Sw-spec/unit-test-and-mock

CounterView.kt

interface CounterView {
    fun setCounter(value: Int)
}

CounterPresenter.kt

class CounterPresenter(val view: CounterView) {
    var counter: Int = 0

    fun onPlusButtonClicked() {
        counter++
        updateCounterInView()
    }
    fun onMinusButtonClicked() {
        counter--
        updateCounterInView()
    }
    fun onResetButtonClicked() {
        reset()
    }
    fun start() {
        reset()
    }

    private fun reset() {
        counter = 0
        updateCounterInView()
    }

    private fun updateCounterInView() {
        view.setCounter(counter)
    }
}