379 lines
12 KiB
JavaScript
379 lines
12 KiB
JavaScript
// Licensed to the Software Freedom Conservancy (SFC) under one
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// or more contributor license agreements. See the NOTICE file
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// distributed with this work for additional information
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// regarding copyright ownership. The SFC licenses this file
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// to you under the Apache License, Version 2.0 (the
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// "License"); you may not use this file except in compliance
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// with the License. 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,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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/**
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* @fileoverview Defines a library that simplifies writing assertions against
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* promised values.
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*
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* > <hr>
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* > __NOTE:__ This module is considered experimental and is subject to
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* > change, or removal, at any time!
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* > <hr>
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*
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* Sample usage:
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*
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* var driver = new webdriver.Builder().build();
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* driver.get('http://www.google.com');
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*
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* assert(driver.getTitle()).equalTo('Google');
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*/
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'use strict';
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const assert = require('assert');
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function trueType(v) {
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if (v === null) {
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return 'null';
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}
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let type = typeof v;
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if (type === 'object') {
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if (Array.isArray(v)) {
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type = 'array';
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}
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}
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return type;
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}
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function checkType(v, want) {
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let got = trueType(v);
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if (got !== want) {
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throw new TypeError('require ' + want + ', but got ' + got);
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}
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return v;
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}
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const checkNumber = v => checkType(v, 'number');
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const checkFunction = v => checkType(v, 'function');
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const checkString = v => checkType(v, 'string');
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const isFunction = v => trueType(v) === 'function';
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const isNumber = v => trueType(v) === 'number';
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const isObject = v => trueType(v) === 'object';
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const isString = v => trueType(v) === 'string';
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function describe(value) {
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let ret;
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try {
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ret = `<${String(value)}>`;
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} catch (e) {
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ret = `<toString failed: ${e.message}>`;
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}
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if (null !== value && void(0) !== value) {
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ret += ` (${trueType(value)})`;
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}
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return ret;
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}
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function evaluate(value, predicate) {
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if (isObject(value) && isFunction(value.then)) {
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return value.then(predicate);
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}
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predicate(value);
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}
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/**
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* @private
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*/
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class Assertion {
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/**
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* @param {?} subject The subject of this assertion.
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* @param {boolean=} opt_invert Whether to invert any assertions performed by
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* this instance.
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*/
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constructor(subject, opt_invert) {
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/** @private {?} */
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this.subject_ = subject;
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/** @private {boolean} */
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this.invert_ = !!opt_invert;
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}
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/**
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* @param {number} expected The minimum permissible value (inclusive).
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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atLeast(expected, opt_message) {
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checkNumber(expected);
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return evaluate(this.subject_, function(actual) {
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if (!isNumber(actual) || actual < expected) {
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assert.fail(actual, expected, opt_message, '>=');
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}
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});
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}
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/**
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* @param {number} expected The maximum permissible value (inclusive).
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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atMost(expected, opt_message) {
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checkNumber(expected);
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return evaluate(this.subject_, function (actual) {
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if (!isNumber(actual) || actual > expected) {
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assert.fail(actual, expected, opt_message, '<=');
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}
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});
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}
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/**
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* @param {number} expected The maximum permissible value (exclusive).
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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greaterThan(expected, opt_message) {
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checkNumber(expected);
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return evaluate(this.subject_, function(actual) {
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if (!isNumber(actual) || actual <= expected) {
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assert.fail(actual, expected, opt_message, '>');
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}
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});
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}
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/**
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* @param {number} expected The minimum permissible value (exclusive).
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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lessThan(expected, opt_message) {
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checkNumber(expected);
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return evaluate(this.subject_, function (actual) {
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if (!isNumber(actual) || actual >= expected) {
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assert.fail(actual, expected, opt_message, '<');
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}
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});
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}
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/**
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* @param {number} expected The desired value.
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* @param {number} epsilon The maximum distance from the desired value.
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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closeTo(expected, epsilon, opt_message) {
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checkNumber(expected);
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checkNumber(epsilon);
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return evaluate(this.subject_, function(actual) {
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checkNumber(actual);
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if (Math.abs(expected - actual) > epsilon) {
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assert.fail(opt_message || `${actual} === ${expected} (± ${epsilon})`);
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}
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});
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}
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/**
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* @param {function(new: ?)} ctor The exptected type's constructor.
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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instanceOf(ctor, opt_message) {
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checkFunction(ctor);
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return evaluate(this.subject_, function(actual) {
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if (!(actual instanceof ctor)) {
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assert.fail(
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opt_message
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|| `${describe(actual)} instanceof ${ctor.name || ctor}`);
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}
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});
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}
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/**
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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isNull(opt_message) {
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return this.isEqualTo(null);
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}
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/**
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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isUndefined(opt_message) {
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return this.isEqualTo(void(0));
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}
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/**
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* Ensures the subject of this assertion is either a string or array
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* containing the given `value`.
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*
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* @param {?} value The value expected to be contained within the subject.
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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contains(value, opt_message) {
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return evaluate(this.subject_, function(actual) {
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if (actual instanceof Map || actual instanceof Set) {
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assert.ok(actual.has(value), opt_message || `${actual}.has(${value})`);
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} else if (Array.isArray(actual) || isString(actual)) {
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assert.ok(
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actual.indexOf(value) !== -1,
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opt_message || `${actual}.indexOf(${value}) !== -1`);
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} else {
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assert.fail(
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`Expected an array, map, set, or string: got ${describe(actual)}`);
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}
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});
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}
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/**
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* @param {string} str The expected suffix.
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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endsWith(str, opt_message) {
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checkString(str);
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return evaluate(this.subject_, function(actual) {
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if (!isString(actual) || !actual.endsWith(str)) {
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assert.fail(actual, str, 'ends with');
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}
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});
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}
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/**
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* @param {string} str The expected prefix.
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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startsWith(str, opt_message) {
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checkString(str);
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return evaluate(this.subject_, function(actual) {
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if (!isString(actual) || !actual.startsWith(str)) {
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assert.fail(actual, str, 'starts with');
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}
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});
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}
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/**
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* @param {!RegExp} regex The regex the subject is expected to match.
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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matches(regex, opt_message) {
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if (!(regex instanceof RegExp)) {
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throw TypeError(`Not a RegExp: ${describe(regex)}`);
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}
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return evaluate(this.subject_, function(actual) {
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if (!isString(actual) || !regex.test(actual)) {
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let message = opt_message
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|| `Expected a string matching ${regex}, got ${describe(actual)}`;
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assert.fail(actual, regex, message);
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}
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});
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}
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/**
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* @param {?} value The unexpected value.
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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notEqualTo(value, opt_message) {
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return evaluate(this.subject_, function(actual) {
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assert.notStrictEqual(actual, value, opt_message);
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});
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}
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/** An alias for {@link #isEqualTo}. */
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equalTo(value, opt_message) {
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return this.isEqualTo(value, opt_message);
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}
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/** An alias for {@link #isEqualTo}. */
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equals(value, opt_message) {
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return this.isEqualTo(value, opt_message);
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}
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/**
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* @param {?} value The expected value.
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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isEqualTo(value, opt_message) {
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return evaluate(this.subject_, function(actual) {
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assert.strictEqual(actual, value, opt_message);
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});
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}
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/**
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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isTrue(opt_message) {
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return this.isEqualTo(true, opt_message);
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}
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/**
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* @param {string=} opt_message An optional failure message.
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* @return {(Promise|undefined)} The result of this assertion, if the subject
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* is a promised-value. Otherwise, the assertion is performed immediately
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* and nothing is returned.
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*/
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isFalse(opt_message) {
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return this.isEqualTo(false, opt_message);
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}
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}
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// PUBLIC API
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/**
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* Creates an assertion about the given `value`.
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* @return {!Assertion} the new assertion.
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*/
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module.exports = function assertThat(value) {
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return new Assertion(value);
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};
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module.exports.Assertion = Assertion; // Exported to help generated docs
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