Auto-Wait in Python with Playwright

 

Mastering Auto-Wait in Python with Playwright: A Step-by-Step Guide

Introduction: In automated testing, timing issues can be a major headache. Waiting for elements to load or actions to complete can introduce flakiness and slow test execution. Playwright, a powerful tool for browser automation, offers a solution to this problem with its autoWait feature. In this article, we’ll explore how you can leverage Playwright’s autoWait feature in Python to streamline your web testing process.

What is a Playwright? Playwright is an open-source automation library developed by Microsoft. It provides a high-level API for automating interactions with web browsers, including Chromium, Firefox, and WebKit. With Playwright, you can write cross-browser tests that run reliably and efficiently.

Understanding AutoWait: autoWait is a feature in Playwright that automatically waits for elements to appear on the page before interacting with them. This helps eliminate the need for explicit wait statements in your test code, making your tests more resilient to timing issues.

· Efficient Handling of Dynamic Content: The playwright can wait for specific network conditions, such as networkidle, ensuring all necessary resources are loaded before proceeding.

· Automatic Waiting: Playwright’s auto-wait function intelligently waits for elements to appear or pages to load, eliminating the need for manual wait times.

· Scenarios Handling: The solution is flexible enough to handle various file formats and workflows by incorporating condition-based waits and validations(awaits)

Setting Up Playwright:

Before diving into auto-waiting and headers, let’s set up Playwright in your Python environment. If you haven’t already installed Playwright, you can do so using pip

we can install it from packages in different environments IDE

Example : Pycharm

pip install playwright

Once installed, we can import Playwright’s sync_api module to write our tests.

Next, you need to install the necessary browser binaries:

playwright install

Creating a Playwright Script with Auto-Wait and Headers

Here’s a step-by-step guide to creating a Playwright script that includes setting custom headers and using auto-waiting techniques.

1. Import Playwright and Initialize the Browser

First, import the required modules and initialize the Playwright browser:

from playwright.sync_api import sync_playwright

def run(playwright):
    browser = playwright.chromium.launch(headless=False)  # Change to True for headless mode
    context = browser.new_context(
        http_headers={
            'User-Agent': 'My Custom User Agent',
            'Accept': 'text/html',
            'Authorization': 'Bearer mytoken'
        }
    )
    page = context.new_page()
    return browser, page

2. Navigate to a URL and Implement Auto-Wait

With the browser and context set up, navigate to a target URL and perform actions with auto-waiting:

Efficient Handling of Dynamic Content:

What is networkidle?

In the context of web automation and testing with Playwright, networkidle is a load state used to determine when a page has finished loading. Specifically, the networkidle state occurs when there are no more than two network connections for at least 500 milliseconds. This implies that the page has likely completed loading all its resources, such as images, scripts, and other assets, making it a useful indicator for when to proceed with further actions in your automated tests.

How does networkidle work?

When you navigate to a URL or perform actions that cause network requests (like clicking a link or submitting a form), Playwright can wait for the networkidle state to ensure that the page has fully loaded before continuing. This is particularly useful for dynamic web applications where elements may load asynchronously.

def perform_actions(page):
    page.goto('https://ecol-vnext-1.sandbox.operations.dynamics.com/')

    # Wait for a specific selector to appear
    page.wait_for_selector('[//button[@id='CompanyButton']')
    
    # Click a link and wait for the navigation to complete
    page.click('//button[@id='NavBarDashboard']')
    
    # Wait for the network to be idle
    page.wait_for_load_state('networkidle')
def close_browser(browser):
    browser.close()

Key Benefits of Using networkidle:

1. Reliability: Ensures that all necessary resources are loaded before interactions, making tests more reliable.
2. Reduced Flakiness: Minimizes timing issues by waiting for the network to be idle, reducing the chances of flaky tests.
3. Simplified Test Scripts: Removes the need for explicit wait statements, making test scripts cleaner and easier to maintain.

When to Use networkidle:

• Navigations: When navigating to a new page and you want to ensure that the page is fully loaded before proceeding.
• Actions Causing Network Requests: After actions that trigger network requests, such as clicks or form submissions, wait for all resources to load.

Another Method of Enabling Autowait :

Automatic Waiting

Timeouts: Playwright allows you to set default timeouts for waiting for elements, making your test scripts more robust.

Enabling AutoWait: To enable autoWait in Playwright, we use the set_default_timeout() method on a Page object. This sets the default timeout for waiting for elements to appear on the page. For example:

from playwright.sync_api import sync_playwright
with sync_playwright() as p:
browser = p.chromium.launch()
page = browser.new_page()
# Enable autoWait with a timeout of 5000 milliseconds (5 seconds)
page.set_default_timeout(5000)

Using AutoWait in Tests: With autoWait enabled, we can write our test code without worrying about adding explicit waits. The playwright will automatically wait for elements to appear before interacting with them. For example:

# Clicking a button that appears after some time
button = page.wait_for_selector('button')
button.click()
# Extracting text from an element
text = page.inner_text('h1')
print('Extracted Text:', text)

Benefits:

Implementing Playwright’s auto-wait function for D365 testing automation offers several benefits:

1. Increased Efficiency: Automation significantly reduces the time required for testing, allowing for quicker turnaround and more frequent testing cycles.
2. Enhanced Flexibility: The solution can handle various scenarios, file formats, and workflows, making it adaptable to different testing requirements.
3. Scalability: The automation solution can easily scale to accommodate larger test suites and more complex scenarios without a proportional increase in testing effort.

Scenarios Handling

Playwright supports asynchronous operations through the await keywords. This allows you to write asynchronous test scripts that can handle dynamic content and asynchronous interactions more efficiently.

Here’s how you can use await with Playwright in Python:

import asyncio
from playwright.async_api import async_playwright

async def run(playwright):
    # Launch a browser
    browser = await playwright.chromium.launch(headless=False)

    # Create a new context
    context = await browser.new_context()

    # Open a new page
    page = await context.new_page()

    # Navigate to a URL
    await page.goto('https://ecol-vnext-1.sandbox.operations.dynamics.com/')

    # Wait for a specific selector to appear
    await page.wait_for_selector('[//button[@id='CompanyButton']')

    # Click a link and wait for navigation to complete
    await page.click('//button[@id='NavBarDashboard']')
    await page.wait_for_load_state('networkidle')

    # Close the browser
    await browser.close()

async def main():
    async with async_playwright() as playwright:
        await run(playwright)

# Run the async function
asyncio.run(main())

Conclusion: Playwright’s autoWait feature simplifies the process of writing reliable and resilient web tests in Python. By automatically waiting for elements to appear on the page, it eliminates the need for explicit wait statements and reduces the likelihood of timing-related issues. Incorporating autoWait into your testing workflow can help you write faster, more reliable tests that provide confidence in your web applications.