JSTests/stress/number-is-integer-intrinsic.js

function assert(b) {
    if (!b)
        throw new Error;
}

function onlyDouble(x) {
    return Number.isInteger(x);
}
noInline(onlyDouble);

let interestingValues = [
    [Infinity, false],
    [-Infinity, false],
    [NaN, false],
    [0.0, true],
    [-0.0, true],
    [90071992547490009021129120, true],
    [9007199254749001000, true],
    [Number.MAX_SAFE_INTEGER, true],
    [Number.MIN_SAFE_INTEGER, true],
    [0.5, false],
    [Math.PI, false],
    [42, true],
    [0, true],
    [-10, true],
    [2147483647, true],
    [-2147483648, true],
    [Number.MIN_VALUE, false],
    [Number.MAX_VALUE, true],
    [-Number.MAX_VALUE, true],
];

for (let i = 0; i < 10000; ++i) {
    for (let [value, result] of interestingValues) {
        assert(onlyDouble(value) === result);
    }
}

interestingValues.push(
    [true, false],
    [false, false],
    [undefined, false],
    [null, false],
    [{}, false],
    [{valueOf() { throw new Error("Should not be called"); }}, false],
    [function(){}, false],
);

function generic(x) {
    return Number.isInteger(x);
}
noInline(generic);

for (let i = 0; i < 10000; ++i) {
    for (let [value, result] of interestingValues) {
        assert(generic(value) === result);
    }
}

function onlyInts(x) {
    return Number.isInteger(x);
}
noInline(onlyInts);

for (let i = 0; i < 10000; ++i) {
    assert(onlyInts(i) === true);
}
for (let i = 0; i < 10000; ++i) {
    for (let [value, result] of interestingValues) {
        assert(onlyInts(value) === result);
    }
}