HTTP_INTERCEPTORS tests.ts

it(`should add Accept header with value 'application/vnd.github.v3.star+json'
    when requested https://api.github.com/*`, () => {
  client.get('https://api.github.com/anything').subscribe();

  const requests = httpMock.match({ method: 'get' });

  expect(requests[0].request.headers.get('Accept'))
    .toEqual('application/vnd.github.v3.star+json');
});

it(`should NOT add Accept header when requested NOT https://api.github.com/*`, () => {
  client.get('https://not-a-github-api.com/anything').subscribe();

  const requests = httpMock.match({ method: 'get' });

  expect(requests[0].request.headers.has('Accept')).toEqual(false);
});