fixture.debugElement.query(By.css('h1'));

fixture.debugElement.query(By.css('class="name"'))

By.css('.classname')          // get by class name
By.css('input[type=radio]')   // get input by type radio
By.css('.parent .child')      // get child who has a parent

//typscript syntax

fixture = TestBed.createComponent(<your component>);

let result = fixture.nativeElement.querySelector('<id attribute name of html element>');

expect(result.id).toEqual("id  of your DOM element.").