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// Copyright 2008 The Closure Library Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/**
* @fileoverview MockRandom provides a mechanism for specifying a stream of
* numbers to expect from calls to Math.random().
*
*/
goog.setTestOnly('goog.testing.MockRandom');
goog.provide('goog.testing.MockRandom');
goog.require('goog.Disposable');
/**
* Class for unit testing code that uses Math.random.
*
* @param {Array<number>} sequence The sequence of numbers to return.
* @param {boolean=} opt_install Whether to install the MockRandom at
* construction time.
* @extends {goog.Disposable}
* @constructor
* @final
*/
goog.testing.MockRandom = function(sequence, opt_install) {
goog.Disposable.call(this);
/**
* The sequence of numbers to be returned by calls to random()
* @type {!Array<number>}
* @private
*/
this.sequence_ = sequence || [];
/**
* The original Math.random function.
* @type {function(): number}
* @private
*/
this.mathRandom_ = Math.random;
/**
* Whether to throw an exception when Math.random() is called when there is
* nothing left in the sequence.
* @type {boolean}
* @private
*/
this.strictlyFromSequence_ = false;
if (opt_install) {
this.install();
}
};
goog.inherits(goog.testing.MockRandom, goog.Disposable);
/**
* Whether this MockRandom has been installed.
* @type {boolean}
* @private
*/
goog.testing.MockRandom.prototype.installed_;
/**
* Installs this MockRandom as the system number generator.
*/
goog.testing.MockRandom.prototype.install = function() {
if (!this.installed_) {
Math.random = goog.bind(this.random, this);
this.installed_ = true;
}
};
/**
* @return {number} The next number in the sequence. If there are no more values
* left, this will return a random number, unless
* {@code this.strictlyFromSequence_} is true, in which case an error will
* be thrown.
*/
goog.testing.MockRandom.prototype.random = function() {
if (this.hasMoreValues()) {
return this.sequence_.shift();
}
if (this.strictlyFromSequence_) {
throw new Error('No numbers left in sequence.');
}
return this.mathRandom_();
};
/**
* @return {boolean} Whether there are more numbers left in the sequence.
*/
goog.testing.MockRandom.prototype.hasMoreValues = function() {
return this.sequence_.length > 0;
};
/**
* Injects new numbers into the beginning of the sequence.
* @param {!Array<number>|number} values Number or array of numbers to inject.
*/
goog.testing.MockRandom.prototype.inject = function(values) {
if (goog.isArray(values)) {
this.sequence_ = values.concat(this.sequence_);
} else {
this.sequence_.splice(0, 0, values);
}
};
/**
* Uninstalls the MockRandom.
*/
goog.testing.MockRandom.prototype.uninstall = function() {
if (this.installed_) {
Math.random = this.mathRandom_;
this.installed_ = false;
}
};
/** @override */
goog.testing.MockRandom.prototype.disposeInternal = function() {
this.uninstall();
delete this.sequence_;
delete this.mathRandom_;
goog.testing.MockRandom.superClass_.disposeInternal.call(this);
};
/**
* @param {boolean} strictlyFromSequence Whether to throw an exception when
* Math.random() is called when there is nothing left in the sequence.
*/
goog.testing.MockRandom.prototype.setStrictlyFromSequence = function(
strictlyFromSequence) {
this.strictlyFromSequence_ = strictlyFromSequence;
};
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