function assertValidEntry(entry) {
  const timingProps = [
    'connectEnd',
    'connectStart',
    'domComplete',
    'domContentLoadedEventEnd',
    'domContentLoadedEventStart',
    'domInteractive',
    'domainLookupEnd',
    'domainLookupStart',
    'fetchStart',
    'loadEventEnd',
    'loadEventStart',
    'redirectEnd',
    'redirectStart',
    'requestStart',
    'responseEnd',
    'responseStart',
    'secureConnectionStart',
    'startTime',
    'unloadEventEnd',
    'unloadEventStart',
  ];

  assert.strictEqual(entry.entryType, 'navigation');
  for (const timingProp of timingProps) {
    assert(entry[timingProp] >= 0);
  }
}
Accepts a PerformanceNavigationTimingEntry (or shim) and asserts that it
has all the expected properties.
@param {Object} entry