BasicMarbleTestRxJs

gistfile1.txt

    test('test rxjs marble', async () => {
        const testScheduler = new TestScheduler((actual, expected) => {
            expect(actual).toEqual(expected);
        });

        const fetchUserEpic = (action$, state$, { getJSON }) => action$.pipe(
            ofType('FETCH_USER'),
            mergeMap(action =>
                getJSON(`https://api.github.com/users/${action.id}`).pipe(
                    map(response => ({ type: 'FETCH_USER_FULFILLED', response }))
                )
            )
        );
        testScheduler.run(({ hot, cold, expectObservable }) => {
            const action$ = hot('-a', {
                a: { type: 'FETCH_USER', id: '123' },
            });
            const state$ = null;
            const dependencies = {
                getJSON: url => cold('--a', {
                    a: { url },
                }),
            }
            const output$ = fetchUserEpic(action$, state$, dependencies);
            expectObservable(output$).toBe('---a', {
                a: {
                    type: 'FETCH_USER_FULFILLED',
                    response: {
                        url: 'https://api.github.com/users/123',
                    },
                },
            });

        });


    });