Is the .should('exist') assertion redundant on Cypress?

Question

Let's consider the case where I need to assert if an element exists. There are 2 possible ways of doing this in cypress:

1) cy.get('button').contains('Save') 2) cy.get('button').contains('Save').should('exist') 

In both cases the test will fail if the 'Save' button not exist.

What are the reasons apart from maybe better code readability/maintainability that I should add the .should('exist') to my cypress tests?

Answer 1

For your usecase of asserting whether an element exists, they are indeed redundant.

.contains() yields a DOM element and according to documentation, .should yields the same element it was given as an input. There are some exceptions when .should yields different element (as you can see in the documentation) but in case of using should('exist'), they are really redundant

As you mentioned, I personally also prefer adding should for better readability. Actually I prefer .should('be.visible') because of following scenario - when an element is hidden or is pushed out of the screen because of some CSS issues, it doesn't exist from user perspective. But..

cy.get('button').contains('Save') - passes test

cy.get('button').contains('Save').should('exist') - passes test

cy.get('button').contains('Save').should('be.visible') - fails test

Answer 2

Actually, until v4.0 is released (and this PR is merged), you need to chain should('exist') assertion if you chain any negative assertions yourself. This is because the default should('exist') assertion is skipped when you chain your own assertions.

Not necessary for positive assertions because they won't pass on non-existent elements.

Also see Implicit should 'exist' assertion is not being applied on cy.get() when other assertion.

Below, the element .first-item does not exist but the assertion passes:

describe('test', () => {     it('test', () => {         cy.get('.first-item').should('not.have.class', 'is-selected');     }); });