Using Chrome Device Emulation

You can run test in Chrome's built-in device emulator. To do this, use the emulation browser parameter.

Emulate a Device #

Specify the target device with the device parameter.

testcafe "chrome:emulation:device=iphone X" tests/sample-fixture.js

runner
    .src('tests/sample-fixture.js')
    .browsers('chrome:emulation:device=iphone X')
    .run();

Emulate a Screen Size #

You can configure the device emulator by providing width, height, orientation, etc.

testcafe "chrome:emulation:width=100;height=200;mobile=true;orientation=vertical;touch=true" tests/sample-fixture.js

runner
    .src('tests/sample-fixture.js')
    .browsers('chrome:emulation:width=100;height=200;mobile=true;orientation=vertical;touch=true')
    .run();

Use Emulation in Headless Mode #

You can combine both device emulation and headless mode.

testcafe "chrome:headless:emulation:device=iphone X;cdpPort=9223" tests/sample-fixture.js

runner
    .src('tests/sample-fixture.js')
    .browsers('chrome:headless:emulation:device=iphone X;cdpPort=9223')
    .run();

Use Emulation in Portable Chrome #

To enable device emulation in a portable Chrome, use the browser alias. The path: prefix does not work in this case.

testcafe "chrome:d:\chrome_portable\chrome.exe:emulation:device=iphone X" tests/test.js

Substitute a User Agent #

Use the userAgent parameter to substitute a user agent string.

TestCafe relies on the user agent string to emulate the browser behavior. Tests are not guaranteed to run correctly if you provide a user agent that is invalid or not supported by TestCafe.

You need to escape special characters in the user agent string when you specify it in the command line. These characters include:

• \ (backslash)
• ' (single quote)
• " (double quote)
• , (comma)
• ; (semicolon)
• : (colon)

The way to escape special characters depends on the shell you use. You also need to escape semicolons from the TestCafe argument parser with an additional backslash.

The following examples show user agent strings escaped for bash and PowerShell.

bash

In bash, put a dollar sign before the argument to allow single quotes. Escape special characters with a backslash and use a double backslash for semicolons to escape them from the TestCafe argument parser:

testcafe $'chrome:emulation:userAgent=\'Mozilla/5.0 (Windows NT 10.0\\; Win64\\; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36\'' test.js

PowerShell

In PowerShell, escape special characters with a single quote and use a backslash for semicolons to escape them from the TestCafe argument parser:

testcafe 'chrome:emulation:userAgent=''Mozilla/5.0 (Windows NT 10.0\; Win64\; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36''' test.js

Emulator Parameters #

Use the following parameters to configure Chrome device emulator. Specify them after the emulation parameter as in the examples above.