example.spec.js

import {ActionsObservable as Observable} from 'redux-observable'
import {VirtualTimeScheduler} from 'rxjs/scheduler/VirtualTimeScheduler';

import 'rxjs/add/observable/empty';
import 'rxjs/add/observable/interval';
import 'rxjs/add/operator/delay';
import 'rxjs/add/operator/concat';
import 'rxjs/add/operator/reduce';
import 'rxjs/add/operator/takeUntil';
import 'rxjs/add/operator/switchMap';
import 'rxjs/add/operator/toArray';
import 'rxjs/add/operator/do';

const intervalSeconds = 60;
let scheduler;

const intervalEpic = (action$) => {
    return Observable
        .interval(intervalSeconds * 1000, scheduler)
        .takeUntil(action$.reduce((v, action) => 0, 0))
        .switchMap(() => {
            return Observable.of({
                type: "SOME_ACTION"
            })
        });
};

export function runObservableEpicTest(observable, epic, done, verify) {
    let mockStore = {
        getState() {
            return {};
        }
    };
    Observable
        .empty()
        .concat(epic(observable, mockStore))
        .toArray()
        .do((actions) => verify(actions))
        .subscribe({
            error: (err) => done.fail(err),
            complete: () => done()
        });
}

describe('test with interval', () => {

    beforeEach(() => {
        scheduler = new VirtualTimeScheduler();
    });

    it('should allow testing of interval', (done) => {
        let observable = Observable
            .empty()
            .delay((intervalSeconds + 1) * 1000, scheduler);
        runObservableEpicTest(observable, intervalEpic, done, (actions) => {
            expect(actions).toEqual([
                { type: "SOME_ACTION" }
            ]);
        });
        scheduler.flush();
    });
});

Testing, using VirtualTimeScheduler, a redux-observable epic that uses interval for a regularly occurring event. Note that the scheduler has to be passed through to the epic.