test262/implementation-contributed/javascriptcore/stress/logical-not-masquerades-as-undefined.js

function shouldBe(actual, expected) {
    if (actual !== expected)
        throw new Error('bad value: ' + actual);
}

function test(value)
{
    return !value;
}
noInline(test);

var data = [
    [ {}, true ],
    [ true, true ],
    [ false, false ],
    [ -0, false ],
    [ 1, true ],
    [ 4.2, true ],
    [ NaN, false ],
    [ Infinity, true ],
    [ [], true ],
    [ new Date(), true ],
    [ "", false ],
    [ "" + "" + "", false ],
    [ "Cocoa", true ],
    [ undefined, false ],
    [ null, false ],
    [ Symbol(), true ],
    [ makeMasquerader() , false]
];

for (var i = 0; i < 1e4; ++i) {
    for (let [ value, result ] of data)
        shouldBe(!test(value), result);
}