@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.

USAGE

Add the plugin by running:

tap plugin add @tapjs/clock

Then, you can use it by accessing the t.clock object on any test, which is an instance of the Clock class.

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 if you enter it.

See clock-mock for full API details.