Angular 4 ngOnInit not working when loading the component first time

I Have a component in Angular 4 that and a template to change the route This component is called but does not load anything no server call. If i put the ngOnInit() method content into constructor it works fine. It seems ngOnInit is not called. Anybody please can help i am working on this since last 2 days.

here is my routing configuration.

const testRouting: ModuleWithProviders = RouterModule.forChild([
        { path:'createtest/:id', component:TestComponent, resolve: { test:TestResolver }},
        { path:'createtest', component:TestComponent, resolve: { test:TestResolver }},
        { path:'testlist', component:TestListComponent }
]);


import {Component,OnInit} from '@angular/core'
import {TestService,Test} from '../shared'
import 'rxjs/add/operator/map';
@Component({
    selector:'test-list',
    templateUrl:'./testlist.component.html'
})
export class TestListComponent implements OnInit{
    testList:Array<Test>;
    constructor(private testService:TestService){}
    ngOnInit = ()=>{
        this.testService.getTest()
        .subscribe(
            data=>this.testList = <Array<Test>>data,
            error=>alert(error)
        );
        console.log("ngOnInit");
    }
}

And here is my template to configure routing

<nav class="navbar navbar-light">
  <div class="container">
    <a class="navbar-brand" routerLink="/">SLearn</a>
    <a class="xyz" routerLink="/testlist">Test List</a>
  </div>
</nav>