94 lines
2.2 KiB
JavaScript
94 lines
2.2 KiB
JavaScript
import createEventHub from '~/helpers/event_hub_factory';
|
|
|
|
describe('event bus factory', () => {
|
|
let eventBus;
|
|
|
|
beforeEach(() => {
|
|
eventBus = createEventHub();
|
|
});
|
|
|
|
afterEach(() => {
|
|
eventBus = null;
|
|
});
|
|
|
|
describe('underlying module', () => {
|
|
let mitt;
|
|
|
|
beforeEach(() => {
|
|
jest.resetModules();
|
|
jest.mock('mitt');
|
|
|
|
// eslint-disable-next-line global-require
|
|
mitt = require('mitt');
|
|
mitt.mockReturnValue(() => ({}));
|
|
|
|
const createEventHubActual = jest.requireActual('~/helpers/event_hub_factory').default;
|
|
eventBus = createEventHubActual();
|
|
});
|
|
|
|
it('creates an emitter', () => {
|
|
expect(mitt).toHaveBeenCalled();
|
|
});
|
|
});
|
|
|
|
describe('instance', () => {
|
|
it.each`
|
|
method
|
|
${'on'}
|
|
${'once'}
|
|
${'off'}
|
|
${'emit'}
|
|
`('binds $$method to $method ', ({ method }) => {
|
|
expect(typeof eventBus[method]).toBe('function');
|
|
expect(eventBus[method]).toBe(eventBus[`$${method}`]);
|
|
});
|
|
});
|
|
|
|
describe('once', () => {
|
|
const event = 'foobar';
|
|
let handler;
|
|
|
|
beforeEach(() => {
|
|
jest.spyOn(eventBus, 'on');
|
|
jest.spyOn(eventBus, 'off');
|
|
handler = jest.fn();
|
|
eventBus.once(event, handler);
|
|
});
|
|
|
|
it('calls on internally', () => {
|
|
expect(eventBus.on).toHaveBeenCalled();
|
|
});
|
|
|
|
it('calls handler when event is emitted', () => {
|
|
eventBus.emit(event);
|
|
expect(handler).toHaveBeenCalled();
|
|
});
|
|
|
|
it('calls off when event is emitted', () => {
|
|
eventBus.emit(event);
|
|
expect(eventBus.off).toHaveBeenCalled();
|
|
});
|
|
|
|
it('calls the handler only once when event is emitted multiple times', () => {
|
|
eventBus.emit(event);
|
|
eventBus.emit(event);
|
|
expect(handler).toHaveBeenCalledTimes(1);
|
|
});
|
|
|
|
describe('when the handler thows an error', () => {
|
|
beforeEach(() => {
|
|
handler = jest.fn().mockImplementation(() => {
|
|
throw new Error();
|
|
});
|
|
eventBus.once(event, handler);
|
|
});
|
|
|
|
it('calls off when event is emitted', () => {
|
|
expect(() => {
|
|
eventBus.emit(event);
|
|
}).toThrow();
|
|
expect(eventBus.off).toHaveBeenCalled();
|
|
});
|
|
});
|
|
});
|
|
});
|