double-equals.js 7.15 KB
Newer Older
1
// Copyright 2008 the V8 project authors. All rights reserved.
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
// 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.
 */

34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108
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);

109 110 111 112

(function () {
  var x = new Wrapper(null);
  var y = x, z = x;
113
   testEqual(y, x);
114 115 116 117 118
})();

(function () {
  var x = new Boolean(true);
  var y = x, z = x;
119
   testEqual(y, x);
120 121 122 123 124
})();

(function () {
  var x = new Boolean(false);
  var y = x, z = x;
125
   testEqual(y, x);
126 127
})();

128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232
// 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; });
233
}
234 235 236
testBadConversion(0);
testBadConversion("string");
testBadConversion(true);