Vfrdtyky

I have a component in Angular 5 with simple logic: user have to press a key, the method onKeyDown calculates result value, so in 1st press resault should be 4, in 2th should be 8:

@Component({

    selector: 'app-landing',

    templateUrl: './main.component.html',

    styleUrls: ['./main.component.less']

})



export class MainComponent {

    result = 0;

    cycle = 0;



    constructor() {

        document.addEventListener('keydown', (e) => this.onKeyDown(e), false);

    }



    onKeyDown(e: any) {

        // do something

        sont someConst = 4;

        result = result + someConst;

        cycle++;

        return {

            cycle: cycle,

            result: result

        };

    }

}

Then I whant to do test for this process: I want to simulate the users pressing button and check if results are what I expect:

// pseudo code

DoTest {

    MainComponent instanceForTest = new MainComponent();

    var test_01 = instanceForTest.onKeyDown(13);

    var test_02 = instanceForTest.onKeyDown(13);

    if (

        test_01.wcycle == 1 &&

        test_01.result == 4 

    ){

        Console.WriteLine("Test 01 passed");

    }

    if (

        test_02.wcycle == 2 &&

        test_02.result == 8 

    ){

        Console.WriteLine("Test 02 passed");

    }

}

How do I make this test in ngx?