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Emulation

CPU Performance​

warning

This feature only works with browsers supporting Chrome DevTools Protocol (CDP).

The CPU speed on mobile devices is significantly slower than on computers. Therefore, to emulate CPU speed in puppeteer, there is a method called emulateCPUThrottling.

Example: Slowing Down CPU Speed by 8x​

Let's use this method to slow down CPU speed by 8 times:

it("should open yandex.ru with emulation 8x slower CPU", async function ({ browser }) {
    // Get puppeteer instance
    const puppeteer = await browser.getPuppeteer();

    // Get the first open page (considering it to be currently active)
    const [page] = await puppeteer.pages();

    // Slow down the CPU speed by 8 times
    await page.emulateCPUThrottling(8);

    await browser.url("https://yandex.ru");
});

Network Bandwidth​

warning

This feature only works with browsers supporting Chrome DevTools Protocol (CDP).

A large number of users access services from mobile devices where internet speed can be quite slow or may even drop out intermittently. In webdriverio, we can limit network bandwidth using the throttle method, thereby testing the website's behavior under various network conditions.

Besides custom settings, the throttle method supports the following ready-made presets:

  • offline | online
  • GPRS
  • Regular2G | Good2G
  • Regular3G | Good3G
  • Regular4G
  • DSL
  • WiFi

Example 1: Emulating a 2G Connection​

Let's emulate a 2G connection and open yandex.ru in Chrome with phone emulation:

it("should open yandex.ru with emulation of 2G-connection", async function ({ browser }) {
    // Emulate a 2G connection
    await browser.throttle("Good2G");

    await browser.url("https://yandex.ru");
});

Example 2: Emulating a Network with Given Characteristics​

We can also emulate a connection with specific characteristics:

it("should open yandex.ru with emulation of custom connection", async function ({ browser }) {
    // Emulate a network connection with specified characteristics
    await browser.throttle({
        offline: false, // emulate offline state
        downloadThroughput: (10 * 1024) / 8, // max download bandwidth (byte/sec)
        uploadThroughput: (10 * 1024) / 8, // max upload bandwidth (byte/sec)
        latency: 10, // min latency from sending the request to receiving the response headers
    });

    await browser.url("https://yandex.ru");
});
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