Controlling the clock

Sometimes we had to test something that relies on time interval/timeouts. This kind of waitings could slow down our test suite and we know that's bad. While testing timeouts, remember that Cypress allows you to control the clock. For example, say that we want to show the user a particular message if the registration AJAX requests take more than two seconds... Take a look at the next test

context("Signup flow", () => {
  it("The happy path should work", () => {
    // it allows you to manage manually the front-end clock, see the `cy.tick` call
    cy.clock();

    // ... the rest of the test

    // form submit...
    cy.get("form")
      .within(() => cy.findByText(strings.signUp).click());

    // moves forward the browser clock by 2 seconds
    cy.tick(2000);

    cy.getByText("Please, be patient...").should("be.visible");
  });
});

The above test does not wait for two seconds (a giant wasted amount of time) until the "Please, be patient..." text appears. Instead, it moves the browser clock forward and the test duration saves two precious seconds!

Always remember: do not sacrifice test speed for anything! You are going to take advantage of a fast test every time you launch it (that means hundreds of times)!

Author: Stefano Magni