Testing 500 status response

todo.service.spec.ts

fdescribe('getAllTodos', () => {
    it('should return an empty array if an Interal Server Error occurs', (done) => {
      
      service.getAllTodos().subscribe(
        (data: Todo[]) => {
          expect(data).toBeDefined();
          expect(Array.isArray(data)).toBe(true);
          expect(data.length).toBe(0);
          done()
        },
        (error: HttpErrorResponse) => { fail('The request was supposed to return an empty array') } 
      );

      const testRequest = httpMock.expectOne('https://jsonplaceholder.typicode.com/todos');
      expect(testRequest.request.method).toBe('GET');
      testRequest.flush({}, { status: 500, statusText: 'Internal Server Error' });

    })
  });