Change Browser Window Size

When running Selenium tests on TestMu AI, you can control the browser window resolution to test responsive layouts, verify UI elements at specific breakpoints, and reproduce resolution-dependent bugs. Set the resolution through the resolution capability in LT:Options.

Set Resolution Using the `resolution` Capability

Pass a resolution string in LT:Options to launch the browser at a specific screen size.

Add the resolution capability to your LT:Options configuration. The value is a string in the format widthxheight. If you do not specify a resolution, TestMu AI defaults to 1024x768.

ResolutionTest.java
import org.openqa.selenium.remote.RemoteWebDriver;
import org.openqa.selenium.chrome.ChromeOptions;
import java.net.URL;
import java.util.HashMap;

public class ResolutionTest {
    public static void main(String[] args) throws Exception {
        ChromeOptions browserOptions = new ChromeOptions();
        browserOptions.setPlatformName("Windows 11");
        browserOptions.setBrowserVersion("latest");

        HashMap<String, Object> ltOptions = new HashMap<>();
        ltOptions.put("username", System.getenv("LT_USERNAME"));
        ltOptions.put("accessKey", System.getenv("LT_ACCESS_KEY"));
        ltOptions.put("resolution", "1920x1080");
        ltOptions.put("project", "Resolution Test");
        browserOptions.setCapability("LT:Options", ltOptions);

        RemoteWebDriver driver = new RemoteWebDriver(
            new URL("https://hub.lambdatest.com/wd/hub"), browserOptions);
        driver.get("https://example.com");
        driver.quit();
    }
}

resolution-test.js
const { Builder } = require("selenium-webdriver");
const chrome = require("selenium-webdriver/chrome");

(async function resolutionTest() {
  let options = new chrome.Options();
  options.setPlatform("Windows 11");
  options.setBrowserVersion("latest");

  let ltOptions = {
    username: process.env.LT_USERNAME,
    accessKey: process.env.LT_ACCESS_KEY,
    resolution: "1920x1080",
    project: "Resolution Test",
  };

  const driver = await new Builder()
    .usingServer("https://hub.lambdatest.com/wd/hub")
    .withCapabilities({ ...options.toJSON(), "LT:Options": ltOptions })
    .build();

  await driver.get("https://example.com");
  await driver.quit();
})();

resolution_test.py
import os
from selenium import webdriver
from selenium.webdriver.chrome.options import Options

options = Options()
options.platform_name = "Windows 11"
options.browser_version = "latest"

lt_options = {
    "username": os.environ["LT_USERNAME"],
    "accessKey": os.environ["LT_ACCESS_KEY"],
    "resolution": "1920x1080",
    "project": "Resolution Test",
}
options.set_capability("LT:Options", lt_options)

driver = webdriver.Remote(
    command_executor="https://hub.lambdatest.com/wd/hub",
    options=options,
)
driver.get("https://example.com")
driver.quit()

ResolutionTest.cs
using OpenQA.Selenium;
using OpenQA.Selenium.Chrome;
using OpenQA.Selenium.Remote;

ChromeOptions browserOptions = new ChromeOptions();
browserOptions.PlatformName = "Windows 11";
browserOptions.BrowserVersion = "latest";

Dictionary<string, object> ltOptions = new Dictionary<string, object>();
ltOptions.Add("username", Environment.GetEnvironmentVariable("LT_USERNAME"));
ltOptions.Add("accessKey", Environment.GetEnvironmentVariable("LT_ACCESS_KEY"));
ltOptions.Add("resolution", "1920x1080");
ltOptions.Add("project", "Resolution Test");
browserOptions.AddAdditionalOption("LT:Options", ltOptions);

IWebDriver driver = new RemoteWebDriver(
    new Uri("https://hub.lambdatest.com/wd/hub"), browserOptions);
driver.Navigate().GoToUrl("https://example.com");
driver.Quit();

ResolutionTest.php
<?php
use Facebook\WebDriver\Remote\RemoteWebDriver;
use Facebook\WebDriver\Remote\DesiredCapabilities;

$capabilities = DesiredCapabilities::chrome();
$capabilities->setPlatform("Windows 11");
$capabilities->setCapability("browserVersion", "latest");

$ltOptions = [
    "username" => getenv("LT_USERNAME"),
    "accessKey" => getenv("LT_ACCESS_KEY"),
    "resolution" => "1920x1080",
    "project" => "Resolution Test",
];
$capabilities->setCapability("LT:Options", $ltOptions);

$driver = RemoteWebDriver::create(
    "https://hub.lambdatest.com/wd/hub", $capabilities);
$driver->get("https://example.com");
$driver->quit();

resolution_test.rb
require "selenium-webdriver"

options = Selenium::WebDriver::Options.chrome(
  platform_name: "Windows 11",
  browser_version: "latest",
  "LT:Options" => {
    username: ENV["LT_USERNAME"],
    accessKey: ENV["LT_ACCESS_KEY"],
    resolution: "1920x1080",
    project: "Resolution Test",
  }
)

driver = Selenium::WebDriver.for(
  :remote,
  url: "https://hub.lambdatest.com/wd/hub",
  capabilities: options,
)
driver.navigate.to("https://example.com")
driver.quit

Supported Resolutions

Choose from these predefined screen resolutions when setting the resolution capability.

Resolution	Aspect Ratio	Common Use
1024x768 (default)	4:3	Legacy desktops, older monitors
1280x800	16:10	Older laptops
1280x1024	5:4	Standard desktop monitors
1366x768	16:9	Budget laptops, common breakpoint
1440x900	16:10	MacBook and mid-range laptops
1680x1050	16:10	Large desktop monitors
1600x1200	4:3	Large standard monitors
1920x1080	16:9	Full HD monitors and laptops
1920x1200	16:10	Professional desktop monitors
2048x1536	4:3	High-resolution displays
2560x1440	16:9	QHD monitors