quixote/example/vendor/quixote.js

CSS unit and integration testing

(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.quixote = f()}})(function(){var define,module,exports;return (function(){function r(e,n,t){function o(i,f){if(!n[i]){if(!e[i]){var c="function"==typeof require&&require;if(!f&&c)return c(i,!0);if(u)return u(i,!0);var a=new Error("Cannot find module '"+i+"'");throw a.code="MODULE_NOT_FOUND",a}var p=n[i]={exports:{}};e[i][0].call(p.exports,function(r){var n=e[i][1][r];return o(n||r)},p,p.exports,r,e,n,t)}return n[i].exports}for(var u="function"==typeof require&&require,i=0;i<t.length;i++)o(t[i]);return o}return r})()({1:[function(require,module,exports){
// shim for using process in browser
var process = module.exports = {};

// cached from whatever global is present so that test runners that stub it
// don't break things.  But we need to wrap it in a try catch in case it is
// wrapped in strict mode code which doesn't define any globals.  It's inside a
// function because try/catches deoptimize in certain engines.

var cachedSetTimeout;
var cachedClearTimeout;

function defaultSetTimout() {
    throw new Error('setTimeout has not been defined');
}
function defaultClearTimeout () {
    throw new Error('clearTimeout has not been defined');
}
(function () {
    try {
        if (typeof setTimeout === 'function') {
            cachedSetTimeout = setTimeout;
        } else {
            cachedSetTimeout = defaultSetTimout;
        }
    } catch (e) {
        cachedSetTimeout = defaultSetTimout;
    }
    try {
        if (typeof clearTimeout === 'function') {
            cachedClearTimeout = clearTimeout;
        } else {
            cachedClearTimeout = defaultClearTimeout;
        }
    } catch (e) {
        cachedClearTimeout = defaultClearTimeout;
    }
} ())
function runTimeout(fun) {
    if (cachedSetTimeout === setTimeout) {
        //normal enviroments in sane situations
        return setTimeout(fun, 0);
    }
    // if setTimeout wasn't available but was latter defined
    if ((cachedSetTimeout === defaultSetTimout || !cachedSetTimeout) && setTimeout) {
        cachedSetTimeout = setTimeout;
        return setTimeout(fun, 0);
    }
    try {
        // when when somebody has screwed with setTimeout but no I.E. maddness
        return cachedSetTimeout(fun, 0);
    } catch(e){
        try {
            // When we are in I.E. but the script has been evaled so I.E. doesn't trust the global object when called normally
            return cachedSetTimeout.call(null, fun, 0);
        } catch(e){
            // same as above but when it's a version of I.E. that must have the global object for 'this', hopfully our context correct otherwise it will throw a global error
            return cachedSetTimeout.call(this, fun, 0);
        }
    }


}
function runClearTimeout(marker) {
    if (cachedClearTimeout === clearTimeout) {
        //normal enviroments in sane situations
        return clearTimeout(marker);
    }
    // if clearTimeout wasn't available but was latter defined
    if ((cachedClearTimeout === defaultClearTimeout || !cachedClearTimeout) && clearTimeout) {
        cachedClearTimeout = clearTimeout;
        return clearTimeout(marker);
    }
    try {
        // when when somebody has screwed with setTimeout but no I.E. maddness
        return cachedClearTimeout(marker);
    } catch (e){
        try {
            // When we are in I.E. but the script has been evaled so I.E. doesn't  trust the global object when called normally
            return cachedClearTimeout.call(null, marker);
        } catch (e){
            // same as above but when it's a version of I.E. that must have the global object for 'this', hopfully our context correct otherwise it will throw a global error.
            // Some versions of I.E. have different rules for clearTimeout vs setTimeout
            return cachedClearTimeout.call(this, marker);
        }
    }



}
var queue = [];
var draining = false;
var currentQueue;
var queueIndex = -1;

function cleanUpNextTick() {
    if (!draining || !currentQueue) {
        return;
    }
    draining = false;
    if (currentQueue.length) {
        queue = currentQueue.concat(queue);
    } else {
        queueIndex = -1;
    }
    if (queue.length) {
        drainQueue();
    }
}

function drainQueue() {
    if (draining) {
        return;
    }
    var timeout = runTimeout(cleanUpNextTick);
    draining = true;

    var len = queue.length;
    while(len) {
        currentQueue = queue;
        queue = [];
        while (++queueIndex < len) {
            if (currentQueue) {
                currentQueue[queueIndex].run();
            }
        }
        queueIndex = -1;
        len = queue.length;
    }
    currentQueue = null;
    draining = false;
    runClearTimeout(timeout);
}

process.nextTick = function (fun) {
    var args = new Array(arguments.length - 1);
    if (arguments.length > 1) {
        for (var i = 1; i < arguments.length; i++) {
            args[i - 1] = arguments[i];
        }
    }
    queue.push(new Item(fun, args));
    if (queue.length === 1 && !draining) {
        runTimeout(drainQueue);
    }
};

// v8 likes predictible objects
function Item(fun, array) {
    this.fun = fun;
    this.array = array;
}
Item.prototype.run = function () {
    this.fun.apply(null, this.array);
};
process.title = 'browser';
process.browser = true;
process.env = {};
process.argv = [];
process.version = ''; // empty string to avoid regexp issues
process.versions = {};

function noop() {}

process.on = noop;
process.addListener = noop;
process.once = noop;
process.off = noop;
process.removeListener = noop;
process.removeAllListeners = noop;
process.emit = noop;
process.prependListener = noop;
process.prependOnceListener = noop;

process.listeners = function (name) { return [] }

process.binding = function (name) {
    throw new Error('process.binding is not supported');
};

process.cwd = function () { return '/' };
process.chdir = function (dir) {
    throw new Error('process.chdir is not supported');
};
process.umask = function() { return 0; };

},{}],2:[function(require,module,exports){
(function (setImmediate,clearImmediate){
var nextTick = require('process/browser.js').nextTick;
var apply = Function.prototype.apply;
var slice = Array.prototype.slice;
var immediateIds = {};
var nextImmediateId = 0;

// DOM APIs, for completeness

exports.setTimeout = function() {
  return new Timeout(apply.call(setTimeout, window, arguments), clearTimeout);
};
exports.setInterval = function() {
  return new Timeout(apply.call(setInterval, window, arguments), clearInterval);
};
exports.clearTimeout =
exports.clearInterval = function(timeout) { timeout.close(); };

function Timeout(id, clearFn) {
  this._id = id;
  this._clearFn = clearFn;
}
Timeout.prototype.unref = Timeout.prototype.ref = function() {};
Timeout.prototype.close = function() {
  this._clearFn.call(window, this._id);
};

// Does not start the time, just sets up the members needed.
exports.enroll = function(item, msecs) {
  clearTimeout(item._idleTimeoutId);
  item._idleTimeout = msecs;
};

exports.unenroll = function(item) {
  clearTimeout(item._idleTimeoutId);
  item._idleTimeout = -1;
};

exports._unrefActive = exports.active = function(item) {
  clearTimeout(item._idleTimeoutId);

  var msecs = item._idleTimeout;
  if (msecs >= 0) {
    item._idleTimeoutId = setTimeout(function onTimeout() {
      if (item._onTimeout)
        item._onTimeout();
    }, msecs);
  }
};

// That's not how node.js implements it but the exposed api is the same.
exports.setImmediate = typeof setImmediate === "function" ? setImmediate : function(fn) {
  var id = nextImmediateId++;
  var args = arguments.length < 2 ? false : slice.call(arguments, 1);

  immediateIds[id] = true;

  nextTick(function onNextTick() {
    if (immediateIds[id]) {
      // fn.call() is faster so we optimize for the common use-case
      // @see http://jsperf.com/call-apply-segu
      if (args) {
        fn.apply(null, args);
      } else {
        fn.call(null);
      }
      // Prevent ids from leaking
      exports.clearImmediate(id);
    }
  });

  return id;
};

exports.clearImmediate = typeof clearImmediate === "function" ? clearImmediate : function(id) {
  delete immediateIds[id];
};
}).call(this,require("timers").setImmediate,require("timers").clearImmediate)

},{"process/browser.js":1,"timers":2}],3:[function(require,module,exports){
// Copyright (c) 2015 Titanium I.T. LLC. All rights reserved. For license, see "README" or "LICENSE" file.
"use strict";

var ensure = require("./util/ensure.js");
var oop = require("./util/oop.js");
var shim = require("./util/shim.js");

var Me = module.exports = function Assertable() {
	ensure.unreachable("Assertable is abstract and should not be constructed directly.");
};
Me.extend = oop.extendFn(Me);
oop.makeAbstract(Me, []);

Me.prototype.assert = function assert(expected, message) {
	ensure.signature(arguments, [ Object, [undefined, String] ]);
	if (message === undefined) message = "Differences found";

	var diff = this.diff(expected);
	if (diff !== "") throw new Error(message + ":\n" + diff + "\n");
};

Me.prototype.diff = function diff(expected) {
	ensure.signature(arguments, [ Object ]);

	var result = [];
	var keys = shim.Object.keys(expected);
	var key, oneDiff, descriptor;
	for (var i = 0; i < keys.length; i++) {
		key = keys[i];
		descriptor = this[key];
		ensure.that(
				descriptor !== undefined,
				this + " doesn't have a property named '" + key + "'. Did you misspell it?"
		);
		oneDiff = descriptor.diff(expected[key]);
		if (oneDiff !== "") result.push(oneDiff);
	}

	return result.join("\n");
};

},{"./util/ensure.js":26,"./util/oop.js":27,"./util/shim.js":28}],4:[function(require,module,exports){
// Copyright Titanium I.T. LLC.
"use strict";

var ensure = require("./util/ensure.js");
var QFrame = require("./q_frame.js");
var Size = require("./values/size.js");

var FRAME_WIDTH = 1500;
var FRAME_HEIGHT = 200;

var features = null;

exports.enlargesFrameToPageSize = createDetectionMethod("enlargesFrame");
exports.enlargesFonts = createDetectionMethod("enlargesFonts");
exports.misreportsClipAutoProperty = createDetectionMethod("misreportsClipAuto");
exports.misreportsAutoValuesInClipProperty = createDetectionMethod("misreportsClipValues");
exports.roundsOffPixelCalculations = createDetectionMethod("roundsOffPixelCalculations");

exports.detectBrowserFeatures = function(callback) {
	var frame = QFrame.create(document.body, { width: FRAME_WIDTH, height: FRAME_HEIGHT }, function(err) {
		if (err) {
			return callback(new Error("Error while creating Quixote browser feature detection frame: " + err));
		}
		return detectFeatures(frame, function(err) {
			frame.remove();
			return callback(err);
		});
	});
};

function detectFeatures(frame, callback) {
	try {
		features = {};
		features.enlargesFrame = detectFrameEnlargement(frame, FRAME_WIDTH);
		features.misreportsClipAuto = detectReportedClipAuto(frame);
		features.misreportsClipValues = detectReportedClipPropertyValues(frame);
		features.roundsOffPixelCalculations = detectRoundsOffPixelCalculations(frame);

		detectFontEnlargement(frame, FRAME_WIDTH, function(result) {
			features.enlargesFonts = result;
			frame.remove();
			return callback(null);
		});

	}
	catch(err) {
		features = null;
		return callback(new Error("Error during Quixote browser feature detection: " + err));
	}
}

function createDetectionMethod(propertyName) {
	return function() {
		ensure.signature(arguments, []);
		ensure.that(
			features !== null,
			"Must call quixote.createFrame() before using Quixote browser feature detection."
		);

		return features[propertyName];
	};
}

function detectFrameEnlargement(frame, frameWidth) {
	frame.reset();

	frame.add("<div style='width: " + (frameWidth + 200) + "px'>force scrolling</div>");
	return !frame.viewport().width.value().equals(Size.create(frameWidth));
}

function detectReportedClipAuto(frame) {
	frame.reset();

	var element = frame.add("<div style='clip: auto;'></div>");
	var clip = element.getRawStyle("clip");

	return clip !== "auto";
}

function detectReportedClipPropertyValues(frame) {
	frame.reset();

	var element = frame.add("<div style='clip: rect(auto, auto, auto, auto);'></div>");
	var clip = element.getRawStyle("clip");

	// WORKAROUND IE 8: Provides 'clipTop' etc. instead of 'clip' property
	if (clip === "" && element.getRawStyle("clip-top") === "auto") return false;

	return clip !== "rect(auto, auto, auto, auto)" && clip !== "rect(auto auto auto auto)";
}

function detectRoundsOffPixelCalculations(frame) {
	var element = frame.add("<div style='font-size: 15px;'></div>");
	var size = element.calculatePixelValue("0.5em");

	if (size === 7.5) return false;
	if (size === 8) return true;
	ensure.unreachable("Failure in roundsOffPixelValues() detection: expected 7.5 or 8, but got " + size);
}

function detectFontEnlargement(frame, frameWidth, callback) {
	ensure.that(frameWidth >= 1500, "Detector frame width must be larger than screen to detect font enlargement");
	frame.reset();

	// WORKAROUND IE 8: we use a <div> because the <style> tag can't be added by frame.add(). At the time of this
	// writing, I'm not sure if the issue is with frame.add() or if IE just can't programmatically add <style> tags.
	frame.add("<div><style>p { font-size: 15px; }</style></div>");

	var text = frame.add("<p>arbitrary text</p>");
	frame.add("<p>must have two p tags to work</p>");

	// WORKAROUND IE 8: need to force reflow or getting font-size may fail below
	// This seems to occur when IE is running in a slow VirtualBox VM. There is no test for this line.
	frame.forceReflow();

	// WORKAROUND Safari 8.0.0: timeout required because font is enlarged asynchronously
	setTimeout(function() {
		var fontSize = text.getRawStyle("font-size");
		ensure.that(fontSize !== "", "Expected font-size to be a value");

		// WORKAROUND IE 8: ignores <style> tag we added above
		if (fontSize === "12pt") return callback(false);

		return callback(fontSize !== "15px");
	}, 0);
}

},{"./q_frame.js":22,"./util/ensure.js":26,"./values/size.js":32}],5:[function(require,module,exports){
// Copyright (c) 2014-2017 Titanium I.T. LLC. All rights reserved. For license, see "README" or "LICENSE" file.
"use strict";

var ensure = require("./util/ensure.js");
var shim = require("./util/shim.js");
var QElement = require("./q_element.js");
var QElementList = require("./q_element_list.js");
var QViewport = require("./q_viewport.js");
var QPage = require("./q_page.js");

var Me = module.exports = function BrowsingContext(contentDocument) {
	ensure.signature(arguments, [Object]);

	this.contentWindow = contentDocument.defaultView || contentDocument.parentWindow;
	this.contentDocument = contentDocument;
};

Me.prototype.body = function body() {
	ensure.signature(arguments, []);

	return QElement.create(this.contentDocument.body, "<body>");
};

Me.prototype.viewport = function viewport() {
	ensure.signature(arguments, []);

	return new QViewport(this);
};

Me.prototype.page = function page() {
	ensure.signature(arguments, []);

	return new QPage(this);
};

Me.prototype.add = function add(html, nickname) {
	ensure.signature(arguments, [String, [undefined, String]]);
	return this.body().add(html, nickname);
};

Me.prototype.get = function get(selector, nickname) {
	ensure.signature(arguments, [String, [undefined, String]]);
	if (nickname === undefined) nickname = selector;

	var nodes = this.contentDocument.querySelectorAll(selector);
	ensure.that(nodes.length === 1, "Expected one element to match '" + selector + "', but found " + nodes.length);
	return QElement.create(nodes[0], nickname);
};

Me.prototype.getAll = function getAll(selector, nickname) {
	ensure.signature(arguments, [String, [undefined, String]]);
	if (nickname === undefined) nickname = selector;

	return new QElementList(this.contentDocument.querySelectorAll(selector), nickname);
};

Me.prototype.scroll = function scroll(x, y) {
	ensure.signature(arguments, [Number, Number]);

	this.contentWindow.scroll(x, y);
};

Me.prototype.getRawScrollPosition = function getRawScrollPosition() {
	ensure.signature(arguments, []);

	return {
		x: shim.Window.pageXOffset(this.contentWindow, this.contentDocument),
		y: shim.Window.pageYOffset(this.contentWindow, this.contentDocument)
	};
};

// This method is not tested--don't know how.
Me.prototype.forceReflow = function forceReflow() {
	this.body().toDomElement().offsetTop;
};

Me.prototype.equals = function equals(that) {
	ensure.signature(arguments, [Me]);
	return this.contentWindow === that.contentWindow;
};

},{"./q_element.js":20,"./q_element_list.js":21,"./q_page.js":23,"./q_viewport.js":24,"./util/ensure.js":26,"./util/shim.js":28}],6:[function(require,module,exports){
// Copyright (c) 2017 Titanium I.T. LLC. All rights reserved. For license, see "README" or "LICENSE" file.
"use strict";

var ensure = require("../util/ensure.js");
var PositionDescriptor = require("./position_descriptor.js");
var Position = require("../values/position.js");

var X_DIMENSION = "x";
var Y_DIMENSION = "y";

var Me = module.exports = function AbsolutePosition(dimension, value) {
  ensure.signature(arguments, [ String, Number ]);

  this.should = this.createShould();

  switch(dimension) {
		case X_DIMENSION:
			PositionDescriptor.x(this);
			this._value = Position.x(value);
			break;
		case Y_DIMENSION:
			PositionDescriptor.y(this);
			this._value = Position.y(value);
			break;
		default: ensure.unreachable("Unknown dimension: " + dimension);
  }
  this._dimension = dimension;
};
PositionDescriptor.extend(Me);

Me.x = function(value) {
	ensure.signature(arguments, [ Number ]);
  return new Me(X_DIMENSION, value);
};

Me.y = function(value) {
	ensure.signature(arguments, [ Number ]);
	return new Me(Y_DIMENSION, value);
};

Me.prototype.value = function() {
  return this._value;
};

Me.prototype.toString = function() {
  return this._value + " " + this._dimension + "-coordinate";
};

},{"../util/ensure.js":26,"../values/position.js":30,"./position_descriptor.js":13}],7:[function(require,module,exports){
// Copyright (c) 2014 Titanium I.T. LLC. All rights reserved. For license, see "README" or "LICENSE" file.
"use strict";

var ensure = require("../util/ensure.js");
var PositionDescriptor = require("./position_descriptor.js");

var X_DIMENSION = "x";
var Y_DIMENSION = "y";

var Me = module.exports = function Center(dimension, position1, position2, description) {
	ensure.signature(arguments, [ String, PositionDescriptor, PositionDescriptor, String ]);

	this.should = this.createShould();
	
	if (dimension === X_DIMENSION) PositionDescriptor.x(this);
	else if (dimension === Y_DIMENSION) PositionDescriptor.y(this);
	else ensure.unreachable("Unknown dimension: " + dimension);

	this._dimension = dimension;
	this._position1 = position1;
	this._position2 = position2;
	this._description = description;
};
PositionDescriptor.extend(Me);

Me.x = factoryFn(X_DIMENSION);
Me.y = factoryFn(Y_DIMENSION);

Me.prototype.value = function value() {
	ensure.signature(arguments, []);
	return this._position1.value().midpoint(this._position2.value());
};

Me.prototype.toString = function toString() {
	ensure.signature(arguments, []);
	return this._description;
};

function factoryFn(dimension) {
	return function(position1, position2, description) {
		return new Me(dimension, position1, position2, description);
	};
}

},{"../util/ensure.js":26,"./position_descriptor.js":13}],8:[function(require,module,exports){
// Copyright (c) 2014 Titanium I.T. LLC. All rights reserved. For license, see "README" or "LICENSE" file.
"use strict";

var ensure = require("../util/ensure.js");
var oop = require("../util/oop.js");
var Value = require("../values/value.js");

var Me = module.exports = function Descriptor() {
	ensure.unreachable("Descriptor is abstract and should not be constructed directly.");
};
Me.extend = oop.extendFn(Me);
oop.makeAbstract(Me, [
	"value",
	"toString"
]);

// WORKAROUND IE 8: Doesn't support Object.defineProperty(), which would allow us to create Me.prototype.should
// directly on this class as an accessor method.
// WORKAROUND IE 11: Doesn't support ES6 'class' syntax, which would allow us to use getter methods and inheritance.
Me.prototype.createShould = function createAssert() {
	var self = this;
	return {

		equal: function(expected, message) {
			self.doAssertion(expected, message, function(actualValue, expectedValue, expectedDesc, message) {
				if (!actualValue.equals(expectedValue)) {
					return message + self + " should be " + expectedValue.diff(actualValue) + ".\n" +
						"  Expected: " + expectedDesc + "\n" +
						"  But was:  " + actualValue;
				}
			});
		},

		notEqual: function(expected, message) {
			self.doAssertion(expected, message, function(actualValue, expectedValue, expectedDesc, message) {
				if (actualValue.equals(expectedValue)) {
					return message + self + " shouldn't be " + expectedValue + ".\n" +
						"  Expected: anything but " + expectedDesc + "\n" +
						"  But was:  " + actualValue;
				}
			});
		},

	};
};

Me.prototype.doAssertion = function doAssertion(expected, message, assertFn) {
	message = message === undefined ? "" : message + ": ";
	expected = convertPrimitiveExpectationToValueObjectIfNeeded(this, expected, message);

	var actualValue;
	var expectedValue;
	try {
		actualValue = this.value();
		expectedValue = expected.value();
	}
	catch (err) {
		throw new Error(
			message + "Error in test. Unable to convert descriptors to values.\n" +
			"Error message: " + err.message + "\n" +
			"  'actual' descriptor:   " + this + " (" + oop.instanceName(this) + ")\n" +
			"  'expected' descriptor: " + expected + " (" + oop.instanceName(expected) + ")\n" +
			"If this error is unclear or you think Quixote is at fault, please open\n" +
			"an issue at https://github.com/jamesshore/quixote/issues. Include this\n" +
			"error message and a standalone example test that reproduces the error.\n" +
			"Error stack trace:\n" +
			err.stack
		);
	}

	if (!actualValue.isCompatibleWith(expectedValue)) {
		throwBadExpectation(
			this, oop.instanceName(expected) + " (" + expected + ")", message,
			"Attempted to compare two incompatible types:"
		);
	}

	var expectedDesc = expectedValue.toString();
	if (expected instanceof Me) expectedDesc += " (" + expected + ")";

	var failure;
	try {
		failure = assertFn(actualValue, expectedValue, expectedDesc, message);
	}
	catch (err2) {
		throw new Error(
			message + "Error in test. Unable to perform assertion.\n" +
			"Error message: " + err2.message + "\n" +
			"  'actual' descriptor:   " + this + " (" + oop.instanceName(this) + ")\n" +
			"  'expected' descriptor: " + expected + " (" + oop.instanceName(expected) + ")\n" +
			"  'actual' value:   " + actualValue + " (" + oop.instanceName(actualValue) + ")\n" +
			"  'expected' value: " + expectedValue + " (" + oop.instanceName(expectedValue) + ")\n" +
			"If this error is unclear or you think Quixote is at fault, please open\n" +
			"an issue at https://github.com/jamesshore/quixote/issues. Include this\n" +
			"error message and a standalone example test that reproduces the error.\n"
		);
	}
	if (failure !== undefined) throw new Error(failure);
};


Me.prototype.diff = function diff(expected) {
	// Legacy code, strictly for compatibility with deprecated Assertable.equals() and Assertable.diff() methods.
	// It's weird because we moved to should.equals(), which always throws an exception, but diff returns a string.
	// To avoid duplicating complex logic, we call should.equals() and then unwrap the exception, but only if it's
	// the right kind of exception.
	try {
		this.should.equal(expected);
		return "";
	}
	catch (err) {
		var message = err.message;
		if (message.indexOf("But was:") === -1) throw err;    // it's not an assertion error, it's some other exception
		return message;
	}
};

Me.prototype.convert = function convert(arg, type) {
	// This method is meant to be overridden by subclasses. It should return 'undefined' when an argument
	// can't be converted. In this default implementation, no arguments can be converted, so we always
	// return 'undefined'.
	return undefined;
};

Me.prototype.equals = function equals(that) {
	// Descriptors aren't value objects. They're never equal to anything. But sometimes
	// they're used in the same places value objects are used, and then this method gets called.
	return false;
};

function convertPrimitiveExpectationToValueObjectIfNeeded(self, expected, message) {
	var expectedType = typeof expected;
	if (expected === null) expectedType = "null";

	if (expectedType === "object" && (expected instanceof Me)) return expected;

	if (expected === undefined) {
		throwBadExpectation(
			self, "undefined", message,
			"The 'expected' parameter is undefined. Did you misspell a property name?"
		);
	}
	else if (expectedType === "object") {
		throwBadExpectation(
			self, oop.instanceName(expected), message,
			"The 'expected' parameter should be a descriptor, but it wasn't recognized."
		);
	}
	else {
		var converted = self.convert(expected, expectedType);
		if (converted !== undefined) return converted;

		throwBadExpectation(
			self, expectedType, message,
			"The 'expected' primitive isn't equivalent to the 'actual' descriptor."
		);
	}
}

function throwBadExpectation(self, expectedType, message, headline) {
	throw new Error(
		message + "Error in test. Use a different 'expected' parameter.\n" +
		headline + "\n" +
		"  'actual' type:   " + oop.instanceName(self) + " (" + self + ")\n" +
		"  'expected' type: " + expectedType
	);
}
},{"../util/ensure.js":26,"../util/oop.js":27,"../values/value.js":33}],9:[function(require,module,exports){
// Copyright (c) 2014-2017 Titanium I.T. LLC. All rights reserved. For license, see "README" or "LICENSE" file.
"use strict";

var ensure = require("../util/ensure.js");
var Position = require("../values/position.js");
var PositionDescriptor = require("./position_descriptor.js");

var TOP = "top";
var RIGHT = "right";
var BOTTOM = "bottom";
var LEFT = "left";

var Me = module.exports = function ElementEdge(element, position) {
	var QElement = require("../q_element.js");      // break circular dependency
	ensure.signature(arguments, [QElement, String]);

	this.should = this.createShould();

	if (position === LEFT || position === RIGHT) PositionDescriptor.x(this);
	else if (position === TOP || position === BOTTOM) PositionDescriptor.y(this);
	else ensure.unreachable("Unknown position: " + position);

	this._element = element;
	this._position = position;
};
PositionDescriptor.extend(Me);

Me.top = factoryFn(TOP);
Me.right = factoryFn(RIGHT);
Me.bottom = factoryFn(BOTTOM);
Me.left = factoryFn(LEFT);

Me.prototype.value = function value() {
	ensure.signature(arguments, []);

	var rawPosition = this._element.getRawPosition();
	var edge = rawPosition[this._position];

	var scroll = this._element.context().getRawScrollPosition();
	var rendered = elementRendered(this._element);

	if (this._position === RIGHT || this._position === LEFT) {
		if (!rendered) return Position.noX();
		return Position.x(edge + scroll.x);
	}
	else {
		if (!rendered) return Position.noY();
		return Position.y(edge + scroll.y);
	}
};

Me.prototype.toString = function toString() {
	ensure.signature(arguments, []);
	return this._position + " edge of " + this._element;
};

function factoryFn(position) {
	return function factory(element) {
		return new Me(element, position);
	};
}

function elementRendered(element) {
	var inDom = element.context().body().contains(element);
	var displayNone = element.getRawStyle("display") === "none";

	return inDom && !displayNone;
}

},{"../q_element.js":20,"../util/ensure.js":26,"../values/position.js":30,"./position_descriptor.js":13}],10:[function(require,module,exports){
// Copyright (c) 2016-2017 Titanium I.T. LLC. All rights reserved. For license, see "README" or "LICENSE" file.
"use strict";

var ensure = require("../util/ensure.js");
var RenderState = require("../values/render_state.js");
var Position = require("../values/position.js");
var Descriptor = require("./descriptor.js");
var ElementRenderEdge = require("./element_render_edge.js");
var Span = require("./span.js");
var Center = require("./center.js");

var Me = module.exports = function ElementRender(element) {
	var QElement = require("../q_element.js");      // break circular dependency
	ensure.signature(arguments, [ QElement ]);

	this.should = this.createShould();
	this._element = element;

	// properties
	this.top = ElementRenderEdge.top(element);
	this.right = ElementRenderEdge.right(element);
	this.bottom = ElementRenderEdge.bottom(element);
	this.left = ElementRenderEdge.left(element);

	this.width = Span.create(this.left, this.right, "rendered width of " + element);
	this.height = Span.create(this.top, this.bottom, "rendered height of " + element);

	this.center = Center.x(this.left, this.right, "rendered center of " + element);
	this.middle = Center.y(this.top, this.bottom, "rendered middle of " + element);
};
Descriptor.extend(Me);

Me.create = function create(element) {
	return new Me(element);
};

Me.prototype.value = function value() {
	if (this.top.value().equals(Position.noY())) return RenderState.notRendered();
	else return RenderState.rendered();
};

Me.prototype.toString = function toString() {
	return this._element.toString() + " rendering";
};

Me.prototype.convert = function convert(arg, type) {
	if (type === "boolean") {
		return arg ? RenderState.rendered() : RenderState.notRendered();
	}
};

},{"../q_element.js":20,"../util/ensure.js":26,"../values/position.js":30,"../values/render_state.js":31,"./center.js":7,"./descriptor.js":8,"./element_render_edge.js":11,"./span.js":18}],11:[function(require,module,exports){
// Copyright (c) 2017 Titanium I.T. LLC. All rights reserved. For license, see "README" or "LICENSE" file.
"use strict";

var ensure = require("../util/ensure.js");
var quixote = require("../quixote.js");
var PositionDescriptor = require("./position_descriptor.js");
var Position = require("../values/position.js");
var QPage = require("../q_page.js");
var Size = require("../values/size.js");

var TOP = "top";
var RIGHT = "right";
var BOTTOM = "bottom";
var LEFT = "left";

var Me = module.exports = function ElementVisibleEdge(element, position) {
	var QElement = require("../q_element.js");      // break circular dependency
	ensure.signature(arguments, [ QElement, String ]);

	this.should = this.createShould();

	if (position === LEFT || position === RIGHT) PositionDescriptor.x(this);
	else if (position === TOP || position === BOTTOM) PositionDescriptor.y(this);
	else unknownPosition(position);

	this._element = element;
	this._position = position;
};
PositionDescriptor.extend(Me);

Me.top = factoryFn(TOP);
Me.right = factoryFn(RIGHT);
Me.bottom = factoryFn(BOTTOM);
Me.left = factoryFn(LEFT);

function factoryFn(position) {
	return function factory(element) {
		return new Me(element, position);
	};
}

Me.prototype.toString = function toString() {
	ensure.signature(arguments, []);
	return this._position + " rendered edge of " + this._element;
};

Me.prototype.value = function() {
	var position = this._position;
	var element = this._element;
	var page = element.context().page();

	if (element.top.value().equals(Position.noY())) return notRendered(position);
	if (element.width.value().equals(Size.create(0))) return notRendered(position);
	if (element.height.value().equals(Size.create(0))) return notRendered(position);

	ensure.that(
		!hasClipPathProperty(element),
		"Can't determine element rendering because the element is affected by the 'clip-path' property, " +
		"which Quixote doesn't support."
	);

	var bounds = {
		top: page.top.value(),
		right: null,
		bottom: null,
		left: page.left.value()
	};

	bounds = intersectionWithOverflow(element, bounds);
	bounds = intersectionWithClip(element, bounds);

	var edges = intersection(
		bounds,
		element.top.value(),
		element.right.value(),
		element.bottom.value(),
		element.left.value()
	);

	if (isClippedOutOfExistence(bounds, edges)) return notRendered(position);
	else return edge(edges, position);
};

function hasClipPathProperty(element) {
	var clipPath = element.getRawStyle("clip-path");
	return clipPath !== "none" && clipPath !== "";
}

function intersectionWithOverflow(element, bounds) {
	for (var container = element.parent(); container !== null; container = container.parent()) {
		if (isClippedByAncestorOverflow(element, container)) {
			bounds = intersection(
				bounds,
				container.top.value(),
				container.right.value(),
				container.bottom.value(),
				container.left.value()
			);
		}
	}

	return bounds;
}

function intersectionWithClip(element, bounds) {
	// WORKAROUND IE 8: Doesn't have any way to detect 'clip: auto' value.
	ensure.that(!quixote.browser.misreportsClipAutoProperty(),
		"Can't determine element rendering on this browser because it misreports the value of the" +
		" `clip: auto` property. You can use `quixote.browser.misreportsClipAutoProperty()` to skip this browser."
	);

	for ( ; element !== null; element = element.parent()) {
		var clip = element.getRawStyle("clip");
		if (clip === "auto" || !canBeClippedByClipProperty(element)) continue;

		var clipEdges = normalizeClipProperty(element, clip);
		bounds = intersection(
			bounds,
			clipEdges.top,
			clipEdges.right,
			clipEdges.bottom,
			clipEdges.left
		);
	}

	return bounds;
}

function normalizeClipProperty(element, clip) {
	var clipValues = parseClipProperty(element, clip);

	return {
		top: clipValues[0] === "auto" ?
			element.top.value() :
			element.top.value().plus(Position.y(Number(clipValues[0]))),
		right: clipValues[1] === "auto" ?
			element.right.value() :
			element.left.value().plus(Position.x(Number(clipValues[1]))),
		bottom: clipValues[2] === "auto" ?
			element.bottom.value() :
			element.top.value().plus(Position.y(Number(clipValues[2]))),
		left: clipValues[3] === "auto" ?
			element.left.value() :
			element.left.value().plus(Position.x(Number(clipValues[3])))
	};

	function parseClipProperty(element, clip) {
		// WORKAROUND IE 11, Chrome Mobile 44: Reports 0px instead of 'auto' when computing rect() in clip property.
		ensure.that(!quixote.browser.misreportsAutoValuesInClipProperty(),
			"Can't determine element rendering on this browser because it misreports the value of the `clip`" +
			" property. You can use `quixote.browser.misreportsAutoValuesInClipProperty()` to skip this browser."
		);

		var clipRegex = /rect\((.*?),? (.*?),? (.*?),? (.*?)\)/;
		var matches = clipRegex.exec(clip);
		ensure.that(matches !== null, "Unable to parse clip property: " + clip);

		return [
			parseLength(matches[1], clip),
			parseLength(matches[2], clip),
			parseLength(matches[3], clip),
			parseLength(matches[4], clip)
		];
	}

	function parseLength(pxString, clip) {
		if (pxString === "auto") return pxString;

		var pxRegex = /^(.*?)px$/;
		var matches = pxRegex.exec(pxString);
		ensure.that(matches !== null, "Unable to parse '" + pxString + "' in clip property: " + clip);

		return matches[1];
	}
}

function isClippedByAncestorOverflow(element, ancestor) {
	return canBeClippedByOverflowProperty(element) && hasClippingOverflow(ancestor);
}

function canBeClippedByOverflowProperty(element) {
	var position = element.getRawStyle("position");
	switch (position) {
		case "static":
		case "relative":
		case "absolute":
		case "sticky":
			return true;
		case "fixed":
			return false;
		default:
			ensure.unreachable("Unknown position property: " + position);
	}
}

function hasClippingOverflow(element) {
	return clips("overflow-x") || clips("overflow-y");

	function clips(style) {
		var overflow = element.getRawStyle(style);
		switch (overflow) {
			case "hidden":
			case "scroll":
			case "auto":
				return true;
			case "visible":
				return false;
			default:
				ensure.unreachable("Unknown " + style + " property: " + overflow);
		}
	}
}

function canBeClippedByClipProperty(element) {
	var position = element.getRawStyle("position");
	switch (position) {
		case "absolute":
		case "fixed":
			return true;
		case "static":
		case "relative":
		case "sticky":
			return false;
		default:
			ensure.unreachable("Unknown position property: " + position);
	}
}

function intersection(bounds, top, right, bottom, left) {
	bounds.top = bounds.top.max(top);
	bounds.right = (bounds.right === null) ? right : bounds.right.min(right);
	bounds.bottom = (bounds.bottom === null) ? bottom : bounds.bottom.min(bottom);
	bounds.left = bounds.left.max(left);

	return bounds;
}

function isClippedOutOfExistence(bounds, edges) {
	return (bounds.top.compare(edges.bottom) >= 0) ||
		(bounds.right !== null && bounds.right.compare(edges.left) <= 0) ||
		(bounds.bottom !== null && bounds.bottom.compare(edges.top) <= 0) ||
		(bounds.left.compare(edges.right) >= 0);
}

function notRendered(position) {
	switch(position) {
		case TOP:
		case BOTTOM:
			return Position.noY();
		case LEFT:
		case RIGHT:
			return Position.noX();
		default: unknownPosition(position);
	}
}

function edge(edges, position) {
	switch(position) {
		case TOP: return edges.top;
		case RIGHT: return edges.right;
		case BOTTOM: return edges.bottom;
		case LEFT: return edges.left;
		default: unknownPosition(position);
	}
}

function unknownPosition(position) {
	ensure.unreachable("Unknown position: " + position);
}
},{"../q_element.js":20,"../q_page.js":23,"../quixote.js":25,"../util/ensure.js":26,"../values/position.js":30,"../values/size.js":32,"./position_descriptor.js":13}],12:[function(require,module,exports){
// Copyright (c) 2014 Titanium I.T. LLC. All rights reserved. For license, see "README" or "LICENSE" file.
"use strict";

var ensure = require("../util/ensure.js");
var PositionDescriptor = require("./position_descriptor.js");
var Position = require("../values/position.js");

var TOP = "top";
var RIGHT = "right";
var BOTTOM = "bottom";
var LEFT = "left";

var Me = module.exports = function PageEdge(edge, browsingContext) {
	var BrowsingContext = require("../browsing_context.js");   // break circular dependency
	ensure.signature(arguments, [ String, BrowsingContext ]);

	this.should = this.createShould();

	if (edge === LEFT || edge === RIGHT) PositionDescriptor.x(this);
	else if (edge === TOP || edge === BOTTOM) PositionDescriptor.y(this);
	else ensure.unreachable("Unknown edge: " + edge);

	this._edge = edge;
	this._browsingContext = browsingContext;
};
PositionDescriptor.extend(Me);

Me.top = factoryFn(TOP);
Me.right = factoryFn(RIGHT);
Me.bottom = factoryFn(BOTTOM);
Me.left = factoryFn(LEFT);

Me.prototype.value = function value() {
	ensure.signature(arguments, []);

	var size = pageSize(this._browsingContext.contentDocument);
	switch(this._edge) {
		case TOP: return Position.y(0);
		case RIGHT: return Position.x(size.width);
		case BOTTOM: return Position.y(size.height);
		case LEFT: return Position.x(0);

		default: ensure.unreachable();
	}
};

Me.prototype.toString = function toString() {
	ensure.signature(arguments, []);

	switch(this._edge) {
		case TOP: return "top of page";
		case RIGHT: return "right side of page";
		case BOTTOM: return "bottom of page";
		case LEFT: return "left side of page";

		default: ensure.unreachable();
	}
};

function factoryFn(edge) {
	return function factory(browsingContext) {
		return new Me(edge, browsingContext);
	};
}


// USEFUL READING: http://www.quirksmode.org/mobile/viewports.html
// and http://www.quirksmode.org/mobile/viewports2.html

// API SEMANTICS.
// Ref https://developer.mozilla.org/en-US/docs/Web/API/CSS_Object_Model/Determining_the_dimensions_of_elements
//    getBoundingClientRect().width: sum of bounding boxes of element (the displayed width of the element,
//      including padding and border). Fractional. Applies transformations.
//    clientWidth: visible width of element including padding (but not border). EXCEPT on root element (html), where
//      it is the width of the viewport. Rounds to an integer. Doesn't apply transformations.
//    offsetWidth: visible width of element including padding, border, and scrollbars (if any). Rounds to an integer.
//      Doesn't apply transformations.
//    scrollWidth: entire width of element, including any part that's not visible due to scrollbars. Rounds to
//      an integer. Doesn't apply transformations. Not clear if it includes scrollbars, but I think not. Also
//      not clear if it includes borders or padding. (But from tests, apparently not borders. Except on root
//      element and body element, which have special results that vary by browser.)

// TEST RESULTS: WIDTH
//   ✔ = correct answer
//   ✘ = incorrect answer and diverges from spec
//   ~ = incorrect answer, but matches spec
// BROWSERS TESTED: Safari 6.2.0 (Mac OS X 10.8.5); Mobile Safari 7.0.0 (iOS 7.1); Firefox 32.0.0 (Mac OS X 10.8);
//    Firefox 33.0.0 (Windows 7); Chrome 38.0.2125 (Mac OS X 10.8.5); Chrome 38.0.2125 (Windows 7); IE 8, 9, 10, 11

// html width style smaller than viewport width; body width style smaller than html width style
//  NOTE: These tests were conducted when correct result was width of border. That has been changed
//  to "width of viewport."
//    html.getBoundingClientRect().width
//      ✘ IE 8, 9, 10: width of viewport
//      ✔ Safari, Mobile Safari, Chrome, Firefox, IE 11: width of html, including border
//    html.clientWidth
//      ~ Safari, Mobile Safari, Chrome, Firefox, IE 8, 9, 10, 11: width of viewport
//    html.offsetWidth
//      ✘ IE 8, 9, 10: width of viewport
//      ✔ Safari, Mobile Safari, Chrome, Firefox, IE 11: width of html, including border
//    html.scrollWidth
//      ✘ IE 8, 9, 10, 11, Firefox: width of viewport
//      ~ Safari, Mobile Safari, Chrome: width of html, excluding border
//    body.getBoundingClientRect().width
//      ~ Safari, Mobile Safari, Chrome, Firefox, IE 8, 9, 10, 11: width of body, including border
//    body.clientWidth
//      ~ Safari, Mobile Safari, Chrome, Firefox, IE 8, 9, 10, 11: width of body, excluding border
//    body.offsetWidth
//      ~ Safari, Mobile Safari, Chrome, Firefox, IE 8, 9, 10, 11: width of body, including border
//    body.scrollWidth
//      ✘ Safari, Mobile Safari, Chrome: width of viewport
//      ~ Firefox, IE 8, 9, 10, 11: width of body, excluding border

// element width style wider than viewport; body and html width styles at default
// BROWSER BEHAVIOR: html and body border extend to width of viewport and not beyond (except on Mobile Safari)
// Correct result is element width + body border-left + html border-left (except on Mobile Safari)
// Mobile Safari uses a layout viewport, so it's expected to include body border-right and html border-right.
//    html.getBoundingClientRect().width
//      ✔ Mobile Safari: element width + body border + html border
//      ~ Safari, Chrome, Firefox, IE 8, 9, 10, 11: viewport width
//    html.clientWidth
//      ✔ Mobile Safari: element width + body border + html border
//      ~ Safari, Chrome, Firefox, IE 8, 9, 10, 11: viewport width
//    html.offsetWidth
//      ✔ Mobile Safari: element width + body border + html border
//      ~ Safari, Chrome, Firefox, IE 8, 9, 10, 11: viewport width
//    html.scrollWidth
//      ✔ Mobile Safari: element width + body border + html border
//      ✘ Safari, Chrome: element width + body border-left (BUT NOT html border-left)
//      ✔ Firefox, IE 8, 9, 10, 11: element width + body border-left + html border-left
//    body.getBoundingClientRect().width
//      ~ Mobile Safari: element width + body border
//      ~ Safari, Chrome, Firefox, IE 8, 9, 10, 11: viewport width - html border
//    body.clientWidth
//      ~ Mobile Safari: element width
//      ~ Safari, Chrome, Firefox, IE 8, 9, 10, 11: viewport width - html border - body border
//    body.offsetWidth
//      ~ Mobile Safari: element width + body border
//      ~ Safari, Chrome, Firefox, IE 8, 9, 10, 11: viewport width - html border
//    body.scrollWidth
//      ✔ Mobile Safari: element width + body border + html border
//      ✔ Safari, Chrome: element width + body border-left + html border-left (matches actual browser)
//      ~ Firefox, IE 8, 9, 10, 11: element width

// TEST RESULTS: HEIGHT
//   ✔ = correct answer
//   ✘ = incorrect answer and diverges from spec
//   ~ = incorrect answer, but matches spec

// html height style smaller than viewport height; body height style smaller than html height style
//  NOTE: These tests were conducted when correct result was height of viewport.
//    html.clientHeight
//      ✔ Safari, Mobile Safari, Chrome, Firefox, IE 8, 9, 10, 11: height of viewport

// element height style taller than viewport; body and html width styles at default
// BROWSER BEHAVIOR: html and body border enclose entire element
// Correct result is element width + body border-top + html border-top + body border-bottom + html border-bottom
//    html.clientHeight
//      ✔ Mobile Safari: element height + all borders
//      ~ Safari, Chrome, Firefox, IE 8, 9, 10, 11: height of viewport
//    html.scrollHeight
//      ✔ Firefox, IE 8, 9, 10, 11: element height + all borders
//      ✘ Safari, Mobile Safari, Chrome: element height + html border-bottom
//    body.scrollHeight
//      ✔ Safari, Mobile Safari, Chrome: element height + all borders
//      ~ Firefox, IE 8, 9, 10, 11: element height (body height - body border)
function pageSize(document) {
	var html = document.documentElement;
	var body = document.body;

// BEST WIDTH ANSWER SO FAR (ASSUMING VIEWPORT IS MINIMUM ANSWER):
	var width = Math.max(body.scrollWidth, html.scrollWidth);

// BEST HEIGHT ANSWER SO FAR (ASSUMING VIEWPORT IS MINIMUM ANSWER):
	var height = Math.max(body.scrollHeight, html.scrollHeight);

	return {
		width: width,
		height: height
	};
}

},{"../browsing_context.js":5,"../util/ensure.js":26,"../values/position.js":30,"./position_descriptor.js":13}],13:[function(require,module,exports){
// Copyright (c) 2014-2017 Titanium I.T. LLC. All rights reserved. For license, see "README" or "LICENSE" file.
/*eslint new-cap: "off" */
"use strict";

var ensure = require("../util/ensure.js");
var oop = require("../util/oop.js");
var Descriptor = require("./descriptor.js");
var Position = require("../values/position.js");

// break circular dependencies
function RelativePosition() {
	return require("./relative_position.js");
}
function AbsolutePosition() {
	return require("./absolute_position.js");
}
function Span() {
	return require("./span.js");
}

var X_DIMENSION = "X";
var Y_DIMENSION = "Y";

var Me = module.exports = function PositionDescriptor(dimension) {
	ensure.signature(arguments, [ String ]);
	ensure.unreachable("PositionDescriptor is abstract and should not be constructed directly.");
};
Descriptor.extend(Me);
Me.extend = oop.extendFn(Me);

function factoryFn(dimension) {
	return function factory(self) {
		// _pdbc: "PositionDescriptor base class." An attempt to prevent name conflicts.
		self._pdbc = { dimension: dimension };
	};
}

Me.x = factoryFn(X_DIMENSION);
Me.y = factoryFn(Y_DIMENSION);

Me.prototype.createShould = function() {
	var self = this;
	var noX = Position.noX();
	var noY = Position.noY();

	var should = Descriptor.prototype.createShould.call(this);
	should.beAbove = assertFn("beAbove", "beLeftOf", Y_DIMENSION, false);
	should.beBelow = assertFn("beBelow", "beRightOf", Y_DIMENSION, true);
	should.beLeftOf = assertFn("beLeftOf", "beAbove", X_DIMENSION, false);
	should.beRightOf = assertFn("beRightOf", "beBelow", X_DIMENSION, true);
	return should;

	function assertFn(functionName, otherAxisName, dimension, shouldBeBigger) {
		return function(expected, message) {
			self.doAssertion(expected, message, function(actualValue, expectedValue, expectedDesc, message) {
				if (self._pdbc.dimension !== dimension) {
					throwCoordinateError(functionName, otherAxisName);
				}
				if (expectedValue.isNone()) {
					throw new Error("'expected' value is not rendered, so relative comparisons aren't possible.");
				}

				var expectedMsg = (shouldBeBigger ? "more than" : "less than") + " " + expectedDesc;

				if (actualValue.isNone()) {
					return errorMessage(message, "rendered", expectedMsg, actualValue);
				}

				var compare = actualValue.compare(expectedValue);
				if ((shouldBeBigger && compare <= 0) || (!shouldBeBigger && compare >= 0)) {
					var nudge = shouldBeBigger ? -1 : 1;
					var shouldBe = "at least " + expectedValue.diff(self.plus(nudge).value());
					return errorMessage(message, shouldBe, expectedMsg, actualValue);
				}
			});
		};
	}

	function throwCoordinateError(functionName, recommendedName) {
		throw new Error(
			"Can't use 'should." + functionName + "()' on " + self._pdbc.dimension +
			" coordinates. Did you mean 'should." + recommendedName + "()'?"
		);
	}

	function errorMessage(message, shouldBe, expected, actual) {
		return message + self + " should be " + shouldBe + ".\n" +
			"  Expected: " + expected + "\n" +
			"  But was:  " + actual;
	}
};

Me.prototype.plus = function(amount) {
	if (this._pdbc.dimension === X_DIMENSION) return RelativePosition().right(this, amount);
	else return RelativePosition().down(this, amount);
};

Me.prototype.minus = function(amount) {
	if (this._pdbc.dimension === X_DIMENSION) return RelativePosition().left(this, amount);
	else return RelativePosition().up(this, amount);
};

Me.prototype.to = function(position, nickname) {
	ensure.signature(arguments, [[ Me, Number ], [ undefined, String ]]);

	if (typeof position === "number") {
		if (this._pdbc.dimension === X_DIMENSION) position = AbsolutePosition().x(position);
		else position = AbsolutePosition().y(position);
	}
	if (this._pdbc.dimension !== position._pdbc