Mastering Playwright TypeScript Tests: A Step-by-Step Guide to Creating Warning Assertions for Non-Critical Failures

As a developer, you understand the importance of writing robust tests to ensure your application’s reliability and scalability. Playwright, a popular browser automation framework, provides an excellent testing mechanism for your web applications. However, when it comes to handling non-critical failures, you need a way to notify your team without breaking the entire test suite. This is where warning assertions come into play. In this article, we’ll delve into the world of Playwright TypeScript tests and explore how to create warning assertions for non-critical failures.

What are Warning Assertions, and Why Do You Need Them?

Warning assertions are a type of assertion that allows you to notify your team about potential issues without failing the entire test. They’re used to handle non-critical failures that don’t necessarily break the application but are still important to address. By using warning assertions, you can:

• Identify and report non-critical issues that might not be immediately noticeable
• Avoid broken builds and failed tests due to minor issues
• Focus on critical failures while still keeping an eye on minor problems

Preparing Your Playwright Environment for Warning Assertions

Before diving into the world of warning assertions, make sure you have the following set up:

1. playwright installed as a dev dependency: npm install --save-dev playwright
2. A basic understanding of Playwright and TypeScript
3. A test framework like Jest or Mocha (we’ll use Jest in this example)

Creating a Simple Playwright Test with Jest

Let’s start with a basic Playwright test using Jest. Create a new file called example.spec.ts and add the following code:

import { test, expect } from '@playwright/test';

test('Example test', async ({ page }) => {
  await page.goto('https://example.com');
  await expect(page).toHaveURL('https://example.com/');
});

This test navigates to https://example.com and verifies the URL. Run the test using the following command:

npx jest

Introducing Warning Assertions with Playwright

Now that we have a basic test in place, let’s explore how to create warning assertions using Playwright’s built-in warn method.

The warn Method

The warn method is used to report non-critical failures without failing the test. It takes two arguments:

• message: A string that describes the warning
• expected: An optional value that can be used to display additional information

Let’s modify our previous test to include a warning assertion:

import { test, expect } from '@playwright/test';

test('Example test with warning', async ({ page }) => {
  await page.goto('https://example.com');
  await expect(page).toHaveURL('https://example.com/');

  // Warning assertion: Check if the page title contains "Example"
  const title = await page.title();
  if (!title.includes('Example')) {
    expect.warn(`Page title does not contain "Example": ${title}`);
  }
});

In this example, we’re checking if the page title contains the string “Example”. If it doesn’t, we use the warn method to report a warning. Note that the test will still pass, but the warning will be displayed in the test output.

Using Custom Warning Messages with Playwright

Sometimes, you need more control over the warning message. Playwright provides a way to customize the warning message using the warn method’s second argument, expected.

import { test, expect } from '@playwright/test';

test('Example test with custom warning message', async ({ page }) => {
  await page.goto('https://example.com');
  await expect(page).toHaveURL('https://example.com/');

  // Warning assertion: Check if the page title contains "Example"
  const title = await page.title();
  if (!title.includes('Example')) {
    expect.warn(`Page title does not contain "Example"`, {
      details: `Expected title to contain "Example", but got "${title}"`,
    });
  }
});

In this example, we’re using the details property to provide additional information about the warning. This can be especially useful when you need to provide more context about the issue.

Handling Multiple Warning Assertions in a Single Test

What if you need to check for multiple non-critical failures in a single test? You can use an array to store warning messages and then use the warn method to report them all at once.

import { test, expect } from '@playwright/test';

test('Example test with multiple warnings', async ({ page }) => {
  await page.goto('https://example.com');
  await expect(page).toHaveURL('https://example.com/');

  const warnings: string[] = [];

  // Check if the page title contains "Example"
  const title = await page.title();
  if (!title.includes('Example')) {
    warnings.push(`Page title does not contain "Example": ${title}`);
  }

  // Check if the page has a meta description
  const metaDescription = await page.$$eval('meta[name="description"]', (elements) => elements[0].getAttribute('content'));
  if (!metaDescription) {
    warnings.push('Meta description is missing');
  }

  // Report all warnings at once
  if (warnings.length > 0) {
    expect.warn('Non-critical failures:', warnings);
  }
});

In this example, we’re storing warning messages in an array and then using the warn method to report all of them at once.

Integrating Warning Assertions with CI/CD Pipelines

Warning assertions can be a valuable asset in your CI/CD pipeline. You can use them to notify your team about non-critical failures before they become critical issues. Here’s an example of how you can integrate warning assertions with a CI/CD pipeline using GitHub Actions:

name: Playwright Tests

on: [push]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v2
      - name: Install dependencies
        run: npm install
      - name: Run tests
        run: npx jest
      - name: Report warnings
        if: failure()
        run: |
          echo "Non-critical failures:"
          cat playwright-tests/warnings.log

In this example, we’re running our Playwright tests using Jest and reporting any warnings using the warn method. The Report warnings step will only run if the test fails, and it will display the warning messages stored in the warnings.log file.

Conclusion

In this article, we’ve explored the world of warning assertions in Playwright TypeScript tests. By using the warn method, you can notify your team about non-critical failures without breaking the entire test suite. We’ve also covered how to create custom warning messages, handle multiple warning assertions, and integrate them with CI/CD pipelines.

Remember, warning assertions are a powerful tool in your testing arsenal. By using them effectively, you can ensure that your application is reliable, scalable, and maintainable.

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Frequently Asked Question

Are you tired of your Playwright TypeScript tests failing unnecessarily due to non-critical issues? Learn how to create warning assertions to handle these pesky errors with ease!