Changing Input properties in Angular after fixture.detectChanges() resulting in strange behaviour

Suppose there are 2 components : AppComponent and TestComponent. I am calling TestComponent using it's directive in the HTML template of AppComponent. Now TestComponent has an @Input() property ( let it be myTitle ).

I am doing unit testing for TestComponent only. For title, i am passing a random value in the test itself. Here is the code for the same :

app.component.html

<span><app-test [myTitle]="title"></app-test></span>

app.component.ts

@Component({
    selector: 'app-root',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.css']
})

export class AppComponent{
    title = {name: 'hello-world'};
}

test.component.html

<p>test works!!{{myTitle.name}}</p>

test.component.ts

@Component({
    selector: 'app-test',
    templateUrl: './test.component.html',
    styleUrls: ['./test.component.css']
})

export class TestComponent implements OnInit{
    @Input() myTitle;

    constructor(){

    }

    ngOnInit():void{
        this.myTitle.name = "Hi!!";
    }
}

test.component.spec.ts

describe('Test component',() =>{
    let temp;
    let component: TestComponent;
    let fixture: ComponentFixture<TestComponent>;

    beforeEach(async(() =>{
       TestBed.configureTestingModule({
           declarations: [TestComponent],
           schemas: [NO_ERRORS_SCHEMA]
       }) 
       .compileComponents();
    }));

    beforeEach(()=>{
        temp = {name: "Heloooo"};
       fixture = TestBed.createComponent(TestComponent);
       component = fixture.componentInstance;
    });

    it('should check First',()=>{
       component.myTitle = temp;
       console.log(component.myTitle.name);
       console.log(temp.name);

       fixture.detectChanges();

       console.log(component.myTitle.name);
       console.log(temp.name);
       expect(component.myTitle.name).toEqual(temp.name);
    });

    it('should check Second',()=>{
       component.myTitle = temp;
       console.log(component.myTitle.name);
       console.log(temp.name);

       fixture.detectChanges();

       temp.name = "Majin Buu";
       console.log(component.myTitle.name);
       console.log(temp.name);
       expect(component.myTitle.name).toEqual(temp.name);
    });
});

Both the test passes and I don't know the reason why.

Questions:

1. Here suppose the input property is a simple string instead of an object, then the cases fail, which is what i was expecting. But for objects it is not working.

2. The console.log which i wrote gives the following output:

Test Case 1:

Heloooo          
Heloooo               
Hi!!          
Hi!!      

Test Case 2:

Heloooo       
Heloooo             
Majin Buu     
Majin Buu     

How come it is showing latest value for object.name? I thought that the object

temp

is local to this scenario.

3. Does fixture.detectChanges() only calls ngOnInit? If no, then how does it work? And how to make sure that the test cases fail for objects too?

I am new to this community, so please help me improve the question if there are any fails.