clock

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cy.clock() overrides native global functions related to time allowing them to be controlled synchronously via cy.tick() or the yielded clock object. This includes controlling:

  • setTimeout
  • clearTimeout
  • setInterval
  • clearInterval
  • Date Objects

The clock starts at the unix epoch (timestamp of 0). This means that when you instantiate new Date in your application, it will have a time of January 1st, 1970.

Syntax

cy.clock()
cy.clock(now)
cy.clock(now, functionNames)
cy.clock(options)
cy.clock(now, options)
cy.clock(now, functionNames, options)

Usage

Correct Usage

cy.clock()

Arguments

now (number)

A timestamp specifying where the clock should start.

functionNames (Array)

Name of native functions that clock should override.

options (Object)

Pass in an options object to change the default behavior of cy.clock().

Option Default Description
log true Displays the command in the Command log

Yields

cy.clock() yields a clock object with the following methods:

  • clock.tick(milliseconds)

    Move the clock the specified number of milliseconds. Any timers within the affected range of time will be called.

  • clock.restore()

    Restore all overridden native functions. This is automatically called between tests, so should not generally be needed.

You can also access the clock object via this.clock in a .then() callback.

Examples

No Args

Create a clock and use it to trigger a setInterval

// your app code
let seconds = 0

setInterval(() => {
  $('#seconds-elapsed').text(++seconds + ' seconds')
}, 1000)
cy.clock()
cy.visit('/index.html')
cy.tick(1000)
cy.get('#seconds-elapsed').should('have.text', '1 seconds')
cy.tick(1000)
cy.get('#seconds-elapsed').should('have.text', '2 seconds')

Access the clock object to synchronously move time

In most cases, it’s easier to use cy.tick() to move time, but you can also use the clock object yielded by cy.clock().

cy.clock().then((clock) => {
  clock.tick(1000)
})

You can call cy.clock() again for this purpose later in a chain if necessary.

cy.clock()
cy.get('input').type('Jane Lane')
cy.clock().then((clock) => {
  clock.tick(1000)
})

The clock object is also available via this.clock in any .then() callback.

cy.clock()
cy.get('form').then(($form) => {
  this.clock.tick(1000)
  // do something with $form ...
})

Access the clock object to restore native functions

In general, it should not be necessary to manually restore the native functions that cy.clock() overrides since this is done automatically between tests. But if you need to, the clock object yield has a .restore() method.

cy.clock().then((clock) => {
  clock.restore()
})

Or via this.clock:

cy.clock()
cy.get('.timer').then(($timer) => {
  this.clock.restore()
  // do something with $timer ...
})

Now

Specify a now timestamp

// your app code
$('#date').text(new Date().toJSON())
const now = new Date(2017, 3, 14).getTime() // April 14, 2017 timestamp

cy.clock(now)
cy.visit('/index.html')
cy.get('#date').contains('2017-04-14')

Function Names

Specify which functions to override

This example below will only override setTimeout and clearTimeout and leave the other time-related functions as they are.

cy.clock(null, ['setTimeout', 'clearTimeout'])

Note that you must specify Date in order to override the current datetime. The example below just affects the current datetime without affecting scheduled timers.

cy.clock(Date.UTC(2018, 10, 30), ['Date'])

Using cy.clock() and cy.tick()

Check out our example recipe testing spying, stubbing and time.

Notes

Iframes

iframes not supported

Note that cy.clock() only applies to the top window on a web page. It will not override the time functions of any iframe embedded on the page.

Behavior

clock behavior before cy.visit()

If you call cy.clock() before visiting a page with cy.visit(), the page’s native global functions will be overridden on window load, before any of your app code runs, so even if setTimeout, for example, is called on page load, it can still be controlled via cy.tick(). This also applies if, during the course of a test, the page under test is reloaded or changed.

Rules

Requirements

  • cy.clock() requires being chained off of cy.

Assertions

  • cy.clock() is a utility command.

  • cy.clock() will not run assertions. Assertions will pass through as if this command did not exist.

Timeouts

  • cy.clock() can not time out.

Command Log

Create a clock and tick it 1 second

cy.clock()
cy.tick(1000)

The command above will display in the Command Log as:

Command Log clock

When clicking on the clock command within the command log, the console outputs the following:

console.log clock command

See also