使用custom commands可以创建自定义命令和替换现有命令。
    自定义命令默认存放在cypress/support/commands.js文件中，它会在任何测试文件被导入之前加载，（定义在cypress/support/index.js中）。

    1. //index.js
    2. // ***********************************************************
    3. // This example support/index.js is processed and
    4. // loaded automatically before your test files.
    5. //
    6. // This is a great place to put global configuration and
    7. // behavior that modifies Cypress.
    8. //
    9. // You can change the location of this file or turn off
    10. // automatically serving support files with the
    11. // 'supportFile' configuration option.
    12. //
    13. // You can read more here:
    14. // https://on.cypress.io/configuration
    15. // ***********************************************************
    17. // Import commands.js using ES2015 syntax:
    18. import './commands'
    20. // Alternatively you can use CommonJS syntax:
    21. // require('./commands')
    23. // beforeEach(function(){
    24. //     cy.log(`当前测试系统环境变量为${JSON.stringify(Cypress.config())}`)
    25. // })

    自定义命令语法如下：

    1. Cypress.Commands.add(name, callbackFn)
    2. Cypress.Commands.add(name, options, callbackFn)
    3. Cypress.Commands.overwrite(name, callbackFn)

    其中：name表示自定义命令的名称，callbackFn表示自定义命令的回调函数，回调函数里定义了自定义函数所需完成的操作步骤。
    options允许定义自定义命令的隐形行为。

    参数 可选值 默认值
    prevSubject true、false、optional false

    实例：kitten登陆

    1. // commands.js
    3. ///<reference types='cypress' />
    5. // kitten 登陆
    6. Cypress.Commands.add('loginRequest', (user, pwd) =>{
    8.     return cy.request({
    9.         method: 'POST',
    10.         url: Cypress.env(Cypress.env('testEnv'))['CODEMAO_HOST']+'/tiger/v3/web/accounts/login',
    11.         form: false,
    12.         failOnStatusCode:true,
    13.         body: {
    14.             "identity": user,
    15.             "password": pwd,
    16.             "pid": "OqMVXvXp"
    17.           },
    18.     }).then((res) =>{
    19.         cy.log(res.status);
    20.         cy.log(res.statusText);
    21.         expect(res.body['user_info']).property('id').to.be.a('number');
    22.     });
    23. });
    1. // testLogin.js
    3. ///<reference types='cypress' />
    5. import LoginPage from '../../pages/login.page'
    7. describe('kitten登陆测试', function(){
    8.     var username = Cypress.env(Cypress.env('testEnv'))['USERNAME'];
    9.     const password = Cypress.env(Cypress.env('testEnv'))['PASSWORD'];
    10.     beforeEach(function(){
    11.         cy.loginRequest(username, password);    //用例集开始执行之前调用自定义命令，即每个用例执行之前就已经是登陆状态
    12.     });
    14.     it('测试登陆成功', function(){
    15.         const logininstance = new LoginPage()
    16.         logininstance.isTargetPage();
    17.         cy.url().should('include', Cypress.env(Cypress.env("testEnv"))['URL'])
    18.     });
    19. });