How to write test case for angular 15

Question

I am trying to write test case for below the code in angular. I am new for test case.So, How to write it in the app.component.spec.ts file? I tried but not working.

app.component.ts:

public arr:[]= [
{
name:'test',
link:'demo'
}];

public dateCheck:number = Date.now();

public ifFoo:boolean = true;

app.component.spec.ts:

it('should verify arr',() => {
component.arr= [
{
name:'test',
link:'demo'
}];
});


it('should verify dateCheck',() => {
 component.dateCheck = Date.now();
});

it('should verify isFoo',() => {
 component.isFoo= true;
});