69 lines
1.9 KiB
JavaScript
69 lines
1.9 KiB
JavaScript
/* global describe beforeEach expect it */
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import inMemoryCache from './in-memory-cache';
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import sinon from 'sinon';
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describe('InMemoryCache', () => {
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let reportErrorStub;
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const theAnswer = 42;
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const before = 'before';
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const after = 'after';
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const emptyCacheValue = null;
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beforeEach(() => {
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reportErrorStub = sinon.spy();
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});
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it('throws if no report function is passed as a second argument', () => {
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expect(() => inMemoryCache(null)).toThrowError(
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'No reportError function specified for this in-memory-cache'
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);
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});
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describe('get', () => {
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it('returns an initial value', () => {
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const cache = inMemoryCache(theAnswer, reportErrorStub);
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expect(cache.get()).toBe(theAnswer);
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});
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});
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describe('update', () => {
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it('updates the cached value', () => {
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const cache = inMemoryCache(before, reportErrorStub);
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cache.update(() => after);
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expect(cache.get()).toBe(after);
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});
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it('can handle promises correctly', done => {
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const cache = inMemoryCache(before, reportErrorStub);
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const promisedUpdate = () => new Promise(resolve => resolve(after));
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cache.update(promisedUpdate).then(() => {
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expect(cache.get()).toBe(after);
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done();
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});
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});
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it('reports errors thrown from the update function', () => {
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const reportErrorStub = sinon.spy();
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const cache = inMemoryCache(before, reportErrorStub);
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const updateError = new Error('An update error');
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const updateThatThrows = () => {
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throw updateError;
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};
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cache.update(updateThatThrows);
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expect(reportErrorStub.calledWith(updateError)).toBe(true);
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});
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});
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describe('clear', () => {
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it('clears the cache', () => {
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expect.assertions(2);
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const cache = inMemoryCache(theAnswer, reportErrorStub);
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expect(cache.get()).toBe(theAnswer);
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cache.clear();
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expect(cache.get()).toBe(emptyCacheValue);
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});
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});
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});
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