Uma forma diferente, mas valida também.
// Arquivo alurapic.cy.js
    const usuarios = require('../../fixtures/usuarios.json');
    usuarios.forEach(usuarios => {
        it.only(`Cadastrar novo usuario ${usuarios.userName} ` , () => {
            cy.register( usuarios.email, usuarios.fullName, usuarios.userName, usuarios.password)
        })
    }); 
//Arquivo gui.commands.js
Cypress.Commands.add('register', (email, fullName, userName, password) => {
    cy.get('p > a').click();
    cy.get('input[formcontrolname="email"]').type(email);
    cy.get('input[formcontrolname="fullName"]').type(fullName);
    cy.get('input[formcontrolname="userName"]').type(userName);
    cy.get('input[formcontrolname="password"]').type(password);
    cy.get('.btn').click();
})//Arquivo usuarios.json
[
    {
        "email": "Iron-man@avengers.com",
        "fullName": "Robert Downey Jr",
        "userName": "ironman",
        "password": "Playboyzinho"
    },
    {
        "email": "Thor@avengers.com",
        "fullName": "Chris Hemsworth",
        "userName": "thor",
        "password": "deusDoTrovão"
    },
    {
        "email": "Hulk@avengers.com",
        "fullName": "Mark Ruffalo",
        "userName": "hulk",
        "password": "hulkEsmaga"
    }
] 
            