test/mjsunit/double-equals.js - v8/v8 - Git at Google

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
 //     * Neither the name of Google Inc. nor the names of its
 //       contributors may be used to endorse or promote products derived
 //       from this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 /**
  * This test uses assert{True,False}(... == ...) instead of
  * assertEquals(..., ...) to not rely on the details of the
  * implementation of assertEquals.
  */

 function testEqual(a, b) {
   assertTrue(a == b);
   assertTrue(b == a);
   assertFalse(a != b);
   assertFalse(b != a);
 }

 function testNotEqual(a, b) {
   assertFalse(a == b);
   assertFalse(b == a);
   assertTrue(a != b);
   assertTrue(b != a);
 }

 // Object where ToPrimitive returns value.
 function Wrapper(value) {
   this.value = value;
   this.valueOf = function () { return this.value; };
 }

 // Object where ToPrimitive returns value by failover to toString when
 // valueOf isn't a function.
 function Wrapper2(value) {
   this.value = value;
   this.valueOf = null;
   this.toString = function () { return this.value; };
 }


 // Compare values of same type.

 // Numbers are equal if same, unless NaN, which isn't equal to anything, and
 // +/-0 being equal.

 testNotEqual(NaN, NaN);
 testNotEqual(NaN, 0);
 testNotEqual(NaN, Infinity);

 testEqual(Number.MAX_VALUE, Number.MAX_VALUE);
 testEqual(Number.MIN_VALUE, Number.MIN_VALUE);
 testEqual(Infinity, Infinity);
 testEqual(-Infinity, -Infinity);

 testEqual(0, 0);
 testEqual(0, -0);
 testEqual(-0, -0);

 testNotEqual(0.9, 1);
 testNotEqual(0.999999, 1);
 testNotEqual(0.9999999999, 1);
 testNotEqual(0.9999999999999, 1);

 // Strings are equal if containing the same code points.

 testEqual('hello', 'hello');
 testEqual('hello', 'hel' + 'lo');
 testEqual('', '');
 testEqual('\u0020\x20', '  ');  // Escapes are not part of the value.

 // Booleans are equal if they are the same.

 testEqual(true, true);
 testEqual(false, false);
 testNotEqual(true, false);

 // Null and undefined are equal to themselves.

 testEqual(null, null);
 testEqual(undefined, undefined);

 // Objects are equal if they are the same object only.

 testEqual(Math, Math);
 testEqual(Object.prototype, Object.prototype);


 (function () {
   var x = new Wrapper(null);
   var y = x, z = x;
    testEqual(y, x);
 })();

 (function () {
   var x = new Boolean(true);
   var y = x, z = x;
    testEqual(y, x);
 })();

 (function () {
   var x = new Boolean(false);
   var y = x, z = x;
    testEqual(y, x);
 })();

 // Test comparing values of different types.

 // Null and undefined are equal to each-other, and to nothing else.
 testEqual(null, undefined);
 testEqual(undefined, null);

 testNotEqual(null, new Wrapper(null));
 testNotEqual(null, 0);
 testNotEqual(null, false);
 testNotEqual(null, "");
 testNotEqual(null, new Object());
 testNotEqual(undefined, new Wrapper(undefined));
 testNotEqual(undefined, 0);
 testNotEqual(undefined, false);
 testNotEqual(undefined, "");
 testNotEqual(undefined, new Object());

 // Numbers compared to Strings will convert the string to a number using
 // the internal ToNumber conversion.

 testEqual(1, '1');
 testEqual(255, '0xff');
 testEqual(0, '\r');  // ToNumber ignores tailing and trailing whitespace.
 testEqual(1e19, '1e19');
 testEqual(Infinity, "Infinity");

 // Booleans compared to anything else will be converted to numbers.
 testEqual(false, 0);
 testEqual(true, 1);
 testEqual(false, "0");  // String also converted to number.
 testEqual(true, "1");

 // Objects compared to Number or String (or Boolean, since that's converted
 // to Number too) is converted to primitive using ToPrimitive with NO HINT.
 // Having no hint means Date gets a string hint, and everything else gets
 // a number hint.

 testEqual(new Boolean(true), true);
 testEqual(new Boolean(true), 1);  // First to primtive boolean, then to number.
 testEqual(new Boolean(false), false);
 testEqual(new Boolean(false), 0);

 testEqual(new Wrapper(true), true);
 testEqual(new Wrapper(true), 1);
 testEqual(new Wrapper(false), false);
 testEqual(new Wrapper(false), 0);

 testEqual(new Wrapper2(true), true);
 testEqual(new Wrapper2(true), 1);
 testEqual(new Wrapper2(false), false);
 testEqual(new Wrapper2(false), 0);

 testEqual(new Number(1), true);
 testEqual(new Number(1), 1);
 testEqual(new Number(0), false);
 testEqual(new Number(0), 0);

 // Date objects convert to string, not number (and the string does not
 // convert to the number).
 testEqual(new Date(42), String(new Date(42)));
 testNotEqual(new Date(42), Number(new Date(42)));
 var dnow = new Date();
 testEqual(dnow, dnow);
 testEqual(dnow, String(dnow));
 testNotEqual(dnow, Number(dnow));

 // Doesn't just call toString, but uses ToPrimitive which tries toString first
 // and valueOf second.
 dnow.toString = null;
 testEqual(dnow, Number(dnow));
 dnow.valueOf = function () { return "42"; };
 testEqual(dnow, 42);
 dnow.toString = function () { return "1"; };
 testEqual(dnow, true);


 // Objects compared to other objects, or to null and undefined, are not
 // converted to primitive.
 testNotEqual(new Wrapper(null), new Wrapper(null));
 testNotEqual(new Boolean(true), new Boolean(true));
 testNotEqual(new Boolean(false), new Boolean(false));
 testNotEqual(new String("a"), new String("a"));
 testNotEqual(new Number(42), new Number(42));
 testNotEqual(new Date(42), new Date(42));
 testNotEqual(new Array(42), new Array(42));
 testNotEqual(new Object(), new Object());

 // Object that can't be converted to primitive.
 var badObject = {
   valueOf: null,
   toString: function() {
     return this;  // Not primitive.
   }
 };

 testEqual(badObject, badObject);
 testNotEqual(badObject, {});
 testNotEqual(badObject, null);
 testNotEqual(badObject, undefined);
 // Forcing conversion will throw.
 function testBadConversion(value) {
   assertThrows(function() { return badObject == value; });
   assertThrows(function() { return badObject != value; });
   assertThrows(function() { return value == badObject; });
   assertThrows(function() { return value != badObject; });
 }
 testBadConversion(0);
 testBadConversion("string");
 testBadConversion(true);

 var s = Symbol();
 testEqual(s, s);
 testEqual(Object(s), s);
 testEqual(new Wrapper(s), s);
 testNotEqual(Object(s), Object(s));
	// Copyright 2008 the V8 project authors. All rights reserved.
	// Redistribution and use in source and binary forms, with or without
	// modification, are permitted provided that the following conditions are
	// met:
	//
	// * Redistributions of source code must retain the above copyright
	// notice, this list of conditions and the following disclaimer.
	// * Redistributions in binary form must reproduce the above
	// copyright notice, this list of conditions and the following
	// disclaimer in the documentation and/or other materials provided
	// with the distribution.
	// * Neither the name of Google Inc. nor the names of its
	// contributors may be used to endorse or promote products derived
	// from this software without specific prior written permission.
	//
	// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

	/**
	* This test uses assert{True,False}(... == ...) instead of
	* assertEquals(..., ...) to not rely on the details of the
	* implementation of assertEquals.
	*/

	function testEqual(a, b) {
	assertTrue(a == b);
	assertTrue(b == a);
	assertFalse(a != b);
	assertFalse(b != a);
	}

	function testNotEqual(a, b) {
	assertFalse(a == b);
	assertFalse(b == a);
	assertTrue(a != b);
	assertTrue(b != a);
	}

	// Object where ToPrimitive returns value.
	function Wrapper(value) {
	this.value = value;
	this.valueOf = function () { return this.value; };
	}

	// Object where ToPrimitive returns value by failover to toString when
	// valueOf isn't a function.
	function Wrapper2(value) {
	this.value = value;
	this.valueOf = null;
	this.toString = function () { return this.value; };
	}


	// Compare values of same type.

	// Numbers are equal if same, unless NaN, which isn't equal to anything, and
	// +/-0 being equal.

	testNotEqual(NaN, NaN);
	testNotEqual(NaN, 0);
	testNotEqual(NaN, Infinity);

	testEqual(Number.MAX_VALUE, Number.MAX_VALUE);
	testEqual(Number.MIN_VALUE, Number.MIN_VALUE);
	testEqual(Infinity, Infinity);
	testEqual(-Infinity, -Infinity);

	testEqual(0, 0);
	testEqual(0, -0);
	testEqual(-0, -0);

	testNotEqual(0.9, 1);
	testNotEqual(0.999999, 1);
	testNotEqual(0.9999999999, 1);
	testNotEqual(0.9999999999999, 1);

	// Strings are equal if containing the same code points.

	testEqual('hello', 'hello');
	testEqual('hello', 'hel' + 'lo');
	testEqual('', '');
	testEqual('\u0020\x20', ' '); // Escapes are not part of the value.

	// Booleans are equal if they are the same.

	testEqual(true, true);
	testEqual(false, false);
	testNotEqual(true, false);

	// Null and undefined are equal to themselves.

	testEqual(null, null);
	testEqual(undefined, undefined);

	// Objects are equal if they are the same object only.

	testEqual(Math, Math);
	testEqual(Object.prototype, Object.prototype);


	(function () {
	var x = new Wrapper(null);
	var y = x, z = x;
	testEqual(y, x);
	})();

	(function () {
	var x = new Boolean(true);
	var y = x, z = x;
	testEqual(y, x);
	})();

	(function () {
	var x = new Boolean(false);
	var y = x, z = x;
	testEqual(y, x);
	})();

	// Test comparing values of different types.

	// Null and undefined are equal to each-other, and to nothing else.
	testEqual(null, undefined);
	testEqual(undefined, null);

	testNotEqual(null, new Wrapper(null));
	testNotEqual(null, 0);
	testNotEqual(null, false);
	testNotEqual(null, "");
	testNotEqual(null, new Object());
	testNotEqual(undefined, new Wrapper(undefined));
	testNotEqual(undefined, 0);
	testNotEqual(undefined, false);
	testNotEqual(undefined, "");
	testNotEqual(undefined, new Object());

	// Numbers compared to Strings will convert the string to a number using
	// the internal ToNumber conversion.

	testEqual(1, '1');
	testEqual(255, '0xff');
	testEqual(0, '\r'); // ToNumber ignores tailing and trailing whitespace.
	testEqual(1e19, '1e19');
	testEqual(Infinity, "Infinity");

	// Booleans compared to anything else will be converted to numbers.
	testEqual(false, 0);
	testEqual(true, 1);
	testEqual(false, "0"); // String also converted to number.
	testEqual(true, "1");

	// Objects compared to Number or String (or Boolean, since that's converted
	// to Number too) is converted to primitive using ToPrimitive with NO HINT.
	// Having no hint means Date gets a string hint, and everything else gets
	// a number hint.

	testEqual(new Boolean(true), true);
	testEqual(new Boolean(true), 1); // First to primtive boolean, then to number.
	testEqual(new Boolean(false), false);
	testEqual(new Boolean(false), 0);

	testEqual(new Wrapper(true), true);
	testEqual(new Wrapper(true), 1);
	testEqual(new Wrapper(false), false);
	testEqual(new Wrapper(false), 0);

	testEqual(new Wrapper2(true), true);
	testEqual(new Wrapper2(true), 1);
	testEqual(new Wrapper2(false), false);
	testEqual(new Wrapper2(false), 0);

	testEqual(new Number(1), true);
	testEqual(new Number(1), 1);
	testEqual(new Number(0), false);
	testEqual(new Number(0), 0);

	// Date objects convert to string, not number (and the string does not
	// convert to the number).
	testEqual(new Date(42), String(new Date(42)));
	testNotEqual(new Date(42), Number(new Date(42)));
	var dnow = new Date();
	testEqual(dnow, dnow);
	testEqual(dnow, String(dnow));
	testNotEqual(dnow, Number(dnow));

	// Doesn't just call toString, but uses ToPrimitive which tries toString first
	// and valueOf second.
	dnow.toString = null;
	testEqual(dnow, Number(dnow));
	dnow.valueOf = function () { return "42"; };
	testEqual(dnow, 42);
	dnow.toString = function () { return "1"; };
	testEqual(dnow, true);


	// Objects compared to other objects, or to null and undefined, are not
	// converted to primitive.
	testNotEqual(new Wrapper(null), new Wrapper(null));
	testNotEqual(new Boolean(true), new Boolean(true));
	testNotEqual(new Boolean(false), new Boolean(false));
	testNotEqual(new String("a"), new String("a"));
	testNotEqual(new Number(42), new Number(42));
	testNotEqual(new Date(42), new Date(42));
	testNotEqual(new Array(42), new Array(42));
	testNotEqual(new Object(), new Object());

	// Object that can't be converted to primitive.
	var badObject = {
	valueOf: null,
	toString: function() {
	return this; // Not primitive.
	}
	};

	testEqual(badObject, badObject);
	testNotEqual(badObject, {});
	testNotEqual(badObject, null);
	testNotEqual(badObject, undefined);
	// Forcing conversion will throw.
	function testBadConversion(value) {
	assertThrows(function() { return badObject == value; });
	assertThrows(function() { return badObject != value; });
	assertThrows(function() { return value == badObject; });
	assertThrows(function() { return value != badObject; });
	}
	testBadConversion(0);
	testBadConversion("string");
	testBadConversion(true);

	var s = Symbol();
	testEqual(s, s);
	testEqual(Object(s), s);
	testEqual(new Wrapper(s), s);
	testNotEqual(Object(s), Object(s));