Unit testing angular custom validator

Question

I'm just starting to learn unit testing and I have this problem that causes unit tests not to run. after running ng test it says Executed 0 out of 0 Success here's my code

validator

export function validateUrl(control: FormControl): ValidationErrors | null {
  let valid = true;
  try{
   let str = control.value;
   if(str.indexOf('://') === -1){
    str = `http://${str}`
    new URL(str);
    control.setValue(str);
  }else{
    new URL(control.value);
  }
 }catch{
   valid = false
 }
  return valid ? null : { invalidUrl: true }
}

spec file

import { TestBed} from "@angular/core/testing";
import { FormControl } from "@angular/forms";
import { validateUrl } from "./web-page-details.component";
describe('maxTextLength', () => {
  beforeEach(() => TestBed.configureTestingModule({}))
   const control = new FormControl();
  it('should return null if input string contains protocol', () => {
   control.setValue('http://test.com');
   expect(validateUrl(control)).toBeNull();
 });
  it('should return null if url doesnt contain protocol', () => {
   control.setValue('test.com');
   expect(validateUrl(control)).toBeNull();
 });
});