5518bac291
* chore: update how we track coverage during unit tests The old method of tracking coverage was causing issues. If a test failed on CI, that test's failure would be lost because the test failing would in turn cause the coverage to fail, but the `process.exit(1)` in the coverage code caused Mocha to not output anything useful. Instead the coverage checker now: * tracks the coverage in memory in a Map (this hasn't changed) * after all tests, writes that to disk in test/coverage.json (which is gitignored) * we then run a single Mocha test that asserts every method was called. This means if the test run fails, the build will fail and give the error about that test run, and that output won't be lost when the coverage then fails too. Co-authored-by: Mathias Bynens <mathias@qiwi.be>
111 lines
3.7 KiB
JavaScript
111 lines
3.7 KiB
JavaScript
/**
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* Copyright 2020 Google Inc. All rights reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/* We want to ensure that all of Puppeteer's public API is tested via our unit
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* tests but we can't use a tool like Istanbul because the way it instruments code
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* unfortunately breaks in Puppeteer where some of that code is then being executed in a browser context.
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*
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* So instead we maintain this coverage code which does the following:
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* * takes every public method that we expect to be tested
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* * replaces it with a method that calls the original but also updates a Map of calls
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* * in an after() test callback it asserts that every public method was called.
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*
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* We run this when COVERAGE=1.
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*/
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const path = require('path');
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const fs = require('fs');
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/**
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* @param {Map<string, boolean>} apiCoverage
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* @param {Object} events
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* @param {string} className
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* @param {!Object} classType
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*/
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function traceAPICoverage(apiCoverage, events, className, classType) {
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className = className.substring(0, 1).toLowerCase() + className.substring(1);
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for (const methodName of Reflect.ownKeys(classType.prototype)) {
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const method = Reflect.get(classType.prototype, methodName);
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if (methodName === 'constructor' || typeof methodName !== 'string' || methodName.startsWith('_') || typeof method !== 'function')
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continue;
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apiCoverage.set(`${className}.${methodName}`, false);
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Reflect.set(classType.prototype, methodName, function(...args) {
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apiCoverage.set(`${className}.${methodName}`, true);
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return method.call(this, ...args);
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});
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}
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if (events[classType.name]) {
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for (const event of Object.values(events[classType.name])) {
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if (typeof event !== 'symbol')
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apiCoverage.set(`${className}.emit(${JSON.stringify(event)})`, false);
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}
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const method = Reflect.get(classType.prototype, 'emit');
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Reflect.set(classType.prototype, 'emit', function(event, ...args) {
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if (typeof event !== 'symbol' && this.listenerCount(event))
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apiCoverage.set(`${className}.emit(${JSON.stringify(event)})`, true);
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return method.call(this, event, ...args);
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});
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}
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}
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const coverageLocation = path.join(__dirname, 'coverage.json');
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const clearOldCoverage = () => {
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try {
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fs.unlinkSync(coverageLocation);
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} catch (error) {
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// do nothing, the file didn't exist
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}
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};
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const writeCoverage = coverage => {
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fs.writeFileSync(coverageLocation, JSON.stringify([...coverage.entries()]));
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};
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const getCoverageResults = () => {
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let contents;
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try {
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contents = fs.readFileSync(coverageLocation, {encoding: 'utf8'});
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} catch (error) {
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console.error('Warning: coverage file does not exist or is not readable.');
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}
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const coverageMap = new Map(JSON.parse(contents));
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return coverageMap;
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};
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const trackCoverage = () => {
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clearOldCoverage();
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const coverageMap = new Map();
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before(() => {
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const api = require('../lib/api');
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const events = require('../lib/Events');
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for (const [className, classType] of Object.entries(api))
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traceAPICoverage(coverageMap, events, className, classType);
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});
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after(() => {
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writeCoverage(coverageMap);
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});
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};
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module.exports = {
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trackCoverage,
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getCoverageResults
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};
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