acelga-bus/src/spec/corebus/executor.spec.ts

An extensible typescript message bus with support for middlewares

import 'jest';
import {Executor} from	'../../corebus/executor';

describe('Executor', () => {
	it('Should execute all functions and then finish', (done) => {
		const ITEMS_QUANTITY = 3;
		const {callbacks, executor} = createBaseExecutor(ITEMS_QUANTITY);

		executor.execStopOnFail()
		.then(() => {
			expect(Array.isArray(callbacks)).toBeTruthy();
			expect(callbacks.length).toBe(ITEMS_QUANTITY);

			callbacks.forEach(callback => {
				expect(callback.mock.calls.length).toBe(1);
			});

			done();
		});
	});

	it('Should allow to add callbacks once created', (done) => {
		const ITEMS_QUANTITY = 3;
		const {
			callbacks,
			executor,
			item,
			callbackFactory,
		} = createBaseExecutor(ITEMS_QUANTITY);

		const fn1 = callbackFactory(item);
		const fn2 = callbackFactory(item);

		executor.add(fn1);
		executor.add(fn2);

		executor.execStopOnFail()
		.then(() => {
			callbacks.forEach(callback => {
				expect(callback.mock.calls.length).toBe(1);
			});

			expect(fn1.mock.calls.length).toBe(1);
			expect(fn2.mock.calls.length).toBe(1);
			done();
		});
	});

	it('Should allow to add several callbacks at the same time once created', (done) => {
		const ITEMS_QUANTITY = 3;
		const {
			callbacks,
			executor,
			item,
			callbackFactory,
		} = createBaseExecutor(ITEMS_QUANTITY);

		const fn1 = callbackFactory(item);
		const fn2 = callbackFactory(item);

		executor.add([fn1, fn2]);

		executor.execStopOnFail()
		.then(() => {
			callbacks.forEach(callback => {
				expect(callback.mock.calls.length).toBe(1);
			});

			expect(fn1.mock.calls.length).toBe(1);
			expect(fn2.mock.calls.length).toBe(1);
			done();
		});
	});

	it('Should stop in case of error', (done) => {
		const ITEMS_QUANTITY = 3;
		const {callbacks, executor} = createBaseExecutor(ITEMS_QUANTITY, (item) => {throw new Error('artifical_error'); });

		executor.execStopOnFail()
		.catch((e) => {
			expect(callbacks.filter(cb => cb.mock.calls.length === 1).length).toBe(1);
			expect(callbacks.filter(cb => cb.mock.calls.length === 0).length).toBe(2);

			expect(e).toBeInstanceOf(Error);
			expect(e.message).toBe('artifical_error');
			done();
		});
	});
});

function createBaseExecutor(len: number, cb?: (item: string) => Promise<any>|void) {
	const item = Math.random() + '';

	let callbackFactory = (itemToTest: string) => jest.fn((result: string) => {
		expect(result).toBe(itemToTest);
	});

	if (cb) callbackFactory = (itemToTest: string) => jest.fn(cb);

	const callbacks = new Array(len).fill(item).map(callbackFactory);

	const executor = new Executor<string>(item, ...callbacks);

	return {callbacks, item, executor, callbackFactory};
}