Cypress tem atributo
cy.get('selector')
.should('have.attr', 'aria-checked', 'true')
Tired Tapir
cy.get('selector')
.should('have.attr', 'aria-checked', 'true')
cy.get('input').invoke('attr', 'placeholder').should('contain', 'username')
cy
.get('nav') // yields <nav>
.should('be.visible') // yields <nav>
.should('have.css', 'font-family') // yields 'sans-serif'
.and('match', /serif/) // yields 'sans-serif'
// have.attr comes from chai-jquery
cy.get('#header a').should('have.attr', 'href', '/users')