Function describeEnv

testing/describes.js:297–369

* Returns a wrapped version of Mocha's describe(), it() and only() methods * that also sets up the provided fixtures and returns the corresponding * environment objects of each fixture to the test method. * @param {function(!Object):!Array<?Fixture>} factory

(factory)

 * @param {function(!Object):!Array<?Fixture>} factory
 */
function describeEnv(factory) {
  /**
   * @param {string} name
   * @param {!Object} spec
   * @param {function(!Object)} fn
   * @param {function(string, function())} describeFunc
   * @param {?boolean} configured
   */
  const templateFunc = function (name, spec, fn, describeFunc, configured) {
    const fixtures = [new SandboxFixture(spec)].concat(
      factory(spec).filter((fixture) => fixture && fixture.isOn())
    );

    return describeFunc(name, () => {
      const env = Object.create(null);

      // Note: If this `beforeEach` function is made async/always returns a
      // Promise, even if it resolves immediately, tests start failing. It's
      // not entirely clear why. Don't refactor this to be an async for-loop
      // like the `afterEach` below.
      beforeEach(() => {
        let totalPromise = undefined;
        // Set up all fixtures.
        fixtures.forEach((fixture) => {
          if (totalPromise) {
            totalPromise = totalPromise.then(() => fixture.setup(env));
          } else {
            const res = fixture.setup(env);
            if (res && typeof res.then == 'function') {
              totalPromise = res;
            }
          }
        });
        return totalPromise;
      });

      afterEach(async () => {
        // Tear down all fixtures in reverse order.
        for (let i = fixtures.length - 1; i >= 0; --i) {
          await fixtures[i].teardown(env);
        }

        // Delete all other keys.
        for (const key in env) {
          delete env[key];
        }
      });

      function execute() {
        if (spec.timeout) {
          this.timeout(spec.timeout);
        }
        fn.call(this, env);
      }

      // Don't re-configure the inner describe() if the outer describes() was
      // already configured.
      if (configured) {