@tapjs/clock

@tapjs/clock

A deterministic mock clock for use in tests involving time.

A mock clock will be available at t.clock. If you call t.clock.enter(), it will monkey-patch all the globals to be tied to the deterministic mock clock implementation. When the test completes, the patched globals will return to their previous state automatically.

For example:

t.test('some timers and such', async t => {
  t.clock.enter()
  let timeoutFired = false
  setTimeout(() => (timeoutFired = true), 100)
  t.clock.advance(50)
  t.equal(timeoutFired, false)
  t.clock.advance(50)
  t.equal(timeoutFired, true)
})

If you aren't using the @tapjs/after plugin, then you'll have to call t.clock.exit() at some point to restore the global timers to their previous states.

See clock-mock for full API details.