@unic/estatico-jest

Puppeteer environment for Jest tests.

Installation

$ npm install --save-dev jest @unic/estatico-jest

Usage

1. Create jest.config.js:

const path = require('path');

const dir = path.dirname(require.resolve('@unic/estatico-jest'));

module.exports = {
  globalSetup: path.join(dir, './setup.js'),
  globalTeardown: path.join(dir, './teardown.js'),
  testEnvironment: path.join(dir, './environment.js'),
  testRegex: 'src/.*\\.test\\.js$',
  // This seems to be the only way for now to pass options to setup.js
  // https://github.com/facebook/jest/issues/5957#issuecomment-422027349
  projects: [{
    // We temporarily run a static webserver where Puppeteer can access our HTML
    puppeteerServer: {
      port: 3000,
      dir: './dist',
      puppeteer: {
        // Our current Teamcity agents expect Puppeteer to run in no-sandbox mode
        args: env.ci ? ['--no-sandbox'] : [],
      },
    },
  }],
};

2. Recommendation: Add jest as npm script:

"scripts": {
    "jest": "jest"
}

3. Optional: Set up Gulp task (requires strip-ansi package):

/**
 * JavaScript testing task
 * Uses Jest with Puppeteer to check for JS errors and run tests
 * Expects an npm script called "jest" which is running jest
 *
 * An alternative would be to use jest.runCLI instead. However, this currently fails
 * due to the teardown script terminating the process in order to close the static webserver.
 *
 * Instead of running this task it is possible to just execute `npm run jest`
 */
gulp.task('js:test', (done) => { // eslint-disable-line consistent-return
  // Skip task when skipping tests
  if (env.skipTests) {
    return done();
  }

  const { spawn } = require('child_process');
  const stripAnsi = require('strip-ansi');

  let failed = false;
  let killed = false;
  let teardownFailed = false;

  const tests = spawn('npm', ['run', 'jest'].concat(env.ci ? ['--', '--ci'] : []), {
    // Add proper output coloring unless in CI env (where this would have weird side-effects)
    stdio: env.ci ? 'pipe' : ['inherit', 'inherit', 'pipe'],
  });

  tests.stderr.on('data', (data) => {
    if (stripAnsi(`${data}`).match(/(Test Suites: (.*?) failed|npm ERR!)/m)) {
      failed = true;
    }

    // Don't treat as failure: Travis seems to kill the whole process for whatever reason
    if (stripAnsi(`${data}`).match(/Killed/m)) {
      killed = true;
    }

    // Don't treat as failure: The web server might have stopped or the process could not be found
    if (stripAnsi(`${data}`).match(/No process found on port/m)) {
      teardownFailed = true;
    }

    process.stderr.write(data);
  });

  tests.on('close', () => {
    if (failed && !env.dev && !killed && !teardownFailed) {
      process.exit(1);
    }

    done();
  });
});

4. Add test files to repository (their file name needs to match the testRegex above).

5. Recommended: Add eslint-plugin-jest with jest/globals to .eslintrc.js.

Example test

describe('Slideshow Tests', () => {
  let page;

  beforeAll(async () => {
    const url = `http://localhost:${global.__STATIC_PORT__}/demo/modules/slideshow/slideshow.html`;

    page = await global.__BROWSER__.newPage();

    page.on('pageerror', console.log);

    await page.goto(url, {
      waitUntil: ['networkidle2']
    });
  });

  afterEach(async () => {
    await page.reload();
  });

  afterAll(async () => {
    await page.close();
  });

  it('should load without error', async () => {
    const text = await page.evaluate(() => document.body.textContent);

    expect(text).toContain('Slideshow');
  });

  it('should return initial image source', async () => {
    const src = await page.evaluate(async () => {
      const img = document.querySelector('[data-slideshow="slide"] img');

      return img.src;
    });

    expect(src).toBe('http://www.fillmurray.com/600/201');
  });

  it('should change the active slide on "next" button click', async () => {
    const currentItem = await page.evaluate(async () => {
      const button = document.querySelector('[data-slideshow="next"]');
      const uuid = document.querySelector('[data-init="slideshow"]').dataset.slideshowInstance;

      await button.click();

      return window.estatico.modules.slideshow.instances[uuid].currentItem;
    });

    expect(currentItem).toBe(1);
  });
});

License

Apache 2.0.