foo.ts

import { marbles } from 'rxjs-marbles/jest';

import { delayUntil } from '../operators';

describe('delayUntil', () => {
  it(
    'if notifier emits nothing and then completes after source emits, emits when notifier completes',
    marbles(m => {
      const source$ = m.cold('  --a--(b|)');
      const notifier$ = m.cold('----------|');
      const expected = '        ----------(ab|)';

      const actual$ = source$.pipe(delayUntil(notifier$));

      m.expect(actual$).toBeObservable(expected);
    }),
  );
  it(
    'if notifier emits after source emits, emits when notifier emits',
    marbles(m => {
      const source$ = m.cold('  --a--(b|)');
      const notifier$ = m.cold('----------a');
      const expected = '        ----------(ab|)';

      const actual$ = source$.pipe(delayUntil(notifier$));

      m.expect(actual$).toBeObservable(expected);
    }),
  );

  it(
    'if notifier completes before source emits, emits when source emits',
    marbles(m => {
      const source$ = m.cold('  -------a--(b|)');
      const notifier$ = m.cold('--|');
      const expected = '        -------a--(b|)';

      const actual$ = source$.pipe(delayUntil(notifier$));

      m.expect(actual$).toBeObservable(expected);
    }),
  );

  it(
    'if notifier emits before source emits, emits when source emits',
    marbles(m => {
      const source$ = m.cold('  -------a--(b|)');
      const notifier$ = m.cold('--a');
      const expected = '        -------a--(b|)';

      const actual$ = source$.pipe(delayUntil(notifier$));

      m.expect(actual$).toBeObservable(expected);
    }),
  );
});