mock

Mock the response of a request. You can define a mock based on a matching glob and corresponding header and status code. Calling the mock method returns a stub object that you can use to modify the response of the web resource.

With the stub object you can then either return a custom response or have the request fail.

There are 3 ways to modify the response:

• return a custom JSON object (for stubbing API request)
• replace web resource with a local file (service a modified JavaScript file) or
• redirect resource to a different url

info

Note that using the mock command requires support for Chrome DevTools protocol. That support is given if you run tests locally in Chromium based browser or if you use a Selenium Grid v4 or higher. This command can not be used when running automated tests in the cloud. Find out more in the Automation Protocols section.

Usage

browser.mock(url, { method, headers, responseHeaders, postData, statusCode })

Parameters

Name	Type	Details
url	String, RegExp	url to mock
filterOptions optional	MockFilterOptions	filter mock resource by additional options
filterOptions.method	String, Function	filter resource by HTTP method
filterOptions.headers	Object, Function	filter resource by specific request headers
filterOptions.responseHeaders	Object, Function	filter resource by specific response headers
filterOptions.postData	String, Function	filter resource by request postData
filterOptions.statusCode	Number, Function	filter resource by response statusCode

Example

mock.js

it('should mock network resources', async () => {
    // via static string
    const userListMock = await browser.mock('**' + '/users/list')
    // or as regular expression
    const userListMock = await browser.mock(/https:\/\/(domainA|domainB)\.com\/.+/)
    // you can also specifying the mock even more by filtering resources
    // by request or response headers, status code, postData, e.g. mock only responses with specific
    // header set and statusCode
    const strictMock = await browser.mock('**', {
        // mock all json responses
        statusCode: 200,
        headers: { 'Content-Type': 'application/json' },
        responseHeaders: { 'Cache-Control': 'no-cache' },
        postData: 'foobar'
    })

    // comparator function
    const apiV1Mock = await browser.mock('**' + '/api/v1', {
        statusCode: (statusCode) => statusCode >= 200 && statusCode <= 203,
        headers: (headers) => headers['Authorization'] && headers['Authorization'].startsWith('Bearer '),
        responseHeaders: (headers) => headers['Impersonation'],
        postData: (data) => typeof data === 'string' && data.includes('foo')
    })
})

it('should modify API responses', async () => {
    // filter by method
    const todoMock = await browser.mock('**' + '/todos', {
        method: 'get'
    })

    // mock an endpoint with a fixed fixture
    todoMock.respond([{
        title: 'Injected Todo',
        order: null,
        completed: false,
        url: "http://todo-backend-express-knex.herokuapp.com/916"
    }])

    // respond with different status code or header
    todoMock.respond([{
        title: 'Injected Todo',
        order: null,
        completed: false,
        url: "http://todo-backend-express-knex.herokuapp.com/916"
    }], {
        statusCode: 404,
        headers: {
            'x-custom-header': 'foobar'
        }
    })
})

it('should modify text assets', async () => {
    const scriptMock = await browser.mock('**' + '/script.min.js')
    scriptMock.respond('./tests/fixtures/script.js')
})

it('should redirect web resources', async () => {
    const headerMock = await browser.mock('**' + '/header.png')
    headerMock.respond('https://media.giphy.com/media/F9hQLAVhWnL56/giphy.gif')

    const pageMock = await browser.mock('https://google.com/')
    pageMock.respond('https://webdriver.io')
    await browser.url('https://google.com')
    console.log(await browser.getTitle()) // returns "WebdriverIO · Next-gen browser and mobile automation test framework for Node.js"
})