I am new to Jasmine tests and I am trying to write unit test for change event,which requires event as mock value in the method argument and I am unable to achieve it.
this is what I have tried

    it('sample test', () => {

    const compiled = fixture1.debugElement;

    const event = {

    preventDefault: jasmine.createSpy(),

    srcElement: jasmine.createSpy()

};

spyOn(component1, 'onChange');

   const select = compiled.query(By.css('#elect-menu')).nativeElement;

   select.value = select.options[1].value;

   select.dispatchEvent(new Event('change'));

   fixture1.detectChanges();

   expect(component1.onChange).toHaveBeenCalled();`

my html code looks like this

<select id=select-menu (change)=onChange($event) (dblclick)=onChange($event)> 

         <option value=default>some value</option>         

         <option  *ngFor=let line of lines  [value]=line.id >{{line.name}}</option>

     </select>  

my component method which will be called on change
onChange($event) {

const selected = parseInt($event.target.value);

switch (selected) {

      case 1: {

        //some logic

         break;

      }

}

I want to write a test case to test positive and negative flows in case 1.