wct-mocha/lib/mocha/extend.js

Client-side library for testing web-components with Mocha.

"use strict";
/**
 * @license
 * Copyright (c) 2018 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at
 * http://polymer.github.io/LICENSE.txt
 * The complete set of authors may be found at
 * http://polymer.github.io/AUTHORS.txt
 * The complete set of contributors may be found at
 * http://polymer.github.io/CONTRIBUTORS.txt
 * Code distributed by Google as part of the polymer project is also
 * subject to an additional IP rights grant found at
 * http://polymer.github.io/PATENTS.txt
 */
Object.defineProperty(exports, "__esModule", { value: true });
var interfaceExtensions = [];
/**
 * Registers an extension that extends the global `Mocha` implementation
 * with new helper methods. These helper methods will be added to the `window`
 * when tests run for both BDD and TDD interfaces.
 */
function extendInterfaces(helperName, helperFactory) {
    interfaceExtensions.push(function () {
        var Mocha = window.Mocha;
        // For all Mocha interfaces (probably just TDD and BDD):
        Object.keys(Mocha.interfaces).forEach(function (interfaceName) {
            if (interfaceName !== 'tdd' && interfaceName !== 'bdd') {
                return;
            }
            // This is the original callback that defines the interface (TDD or
            // BDD):
            var originalInterface = Mocha.interfaces[interfaceName];
            // This is the name of the "teardown" or "afterEach" property for the
            // current interface:
            var teardownProperty = interfaceName === 'tdd' ? 'teardown' : 'afterEach';
            // The original callback is monkey patched with a new one that appends
            // to the global context however we want it to:
            Mocha.interfaces[interfaceName] = function (suite) {
                // Call back to the original callback so that we get the base
                // interface:
                originalInterface.apply(this, arguments);
                // Register a listener so that we can further extend the base
                // interface:
                suite.on('pre-require', function (context, _file, _mocha) {
                    // Capture a bound reference to the teardown function as a
                    // convenience:
                    var teardown = context[teardownProperty].bind(context);
                    // Add our new helper to the testing context. The helper is
                    // generated by a factory method that receives the context,
                    // the teardown function and the interface name and returns
                    // the new method to be added to that context:
                    // tslint:disable-next-line:no-any
                    context[helperName] =
                        helperFactory(context, teardown, interfaceName);
                });
            };
        });
    });
}
exports.extendInterfaces = extendInterfaces;
/**
 * Applies any registered interface extensions. The extensions will be applied
 * as many times as this function is called, so don't call it more than once.
 */
function applyExtensions() {
    interfaceExtensions.forEach(function (applyExtension) {
        applyExtension();
    });
}
exports.applyExtensions = applyExtensions;
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