1function testTimeResolution(highResTimeFunc, funcString) {
2    test(() => {
3        const t0 = highResTimeFunc();
4        let t1 = highResTimeFunc();
5        while (t0 == t1) {
6            t1 = highResTimeFunc();
7        }
8        const epsilon = 1e-5;
9        assert_greater_than_equal(t1 - t0, 0.005 - epsilon, 'The second ' + funcString + ' should be much greater than the first');
10    }, 'Verifies the resolution of ' + funcString + ' is at least 5 microseconds.');
11}
12
13function timeByPerformanceNow() {
14    return performance.now();
15}
16
17function timeByUserTiming() {
18    performance.mark('timer');
19    const time = performance.getEntriesByName('timer')[0].startTime;
20    performance.clearMarks('timer');
21    return time;
22}
23
24testTimeResolution(timeByPerformanceNow, 'performance.now()');
25testTimeResolution(timeByUserTiming, 'entry.startTime');
26