Official Playwright Best Practices Guide
Defining Test Purpose and Scope
One of the first lessons I learned was the importance of clarity when starting a test. Ask yourself:
- What functionality am I testing?
- What is the expected outcome?
- What are the test's boundaries?
For example, when verifying an e-commerce application's checkout flow, define whether you're testing the ability to complete a purchase, inventory updates, or order confirmation emails. Narrowing your scope prevents unnecessary interactions and keeps tests focused.
Examples
Well-Defined Test Purpose: Test login functionality using valid credentials and verify successful redirection.
Scope Control: Skip database checks if the goal is purely to validate UI behavior.
Using TypeScript for Stronger Tests
Early on, I worked with JavaScript in my tests, but as my projects grew, I realized the benefits of TypeScript. Its type safety and IDE support significantly improve test maintainability by catching errors during development and enhancing code readability.
Here’s a simple example:
interface UserCredentials {
username: string;
password: string;
}
const login = ({ username, password }: UserCredentials) => {
cy.get('[data-testid="username"]').type(username);
cy.get('[data-testid="password"]').type(password);
cy.get('[data-testid="login-button"]').click();
};
Using TypeScript ensures that my test inputs are always valid, especially in complex flows involving API responses or structured data. This consistency has saved me hours of debugging.
Writing Readable Tests
Another lesson I learned the hard way is that tests need to be clear and intuitive for anyone on the team, not just developers. Avoid embedding unnecessary logic and focus on leveraging framework-specific syntax for simplicity.
Examples
❌ Complex Logic:
cy.get('.items').then(($items) => {
Array.from($items).forEach(item => {
if (item.innerText.includes('Special')) {
cy.wrap(item).click();
}
});
});
✅ Framework Features:
cy.get('.items')
.contains('Special')
.click();
The second approach is not only cleaner but also leverages Cypress features, reducing the chances of flakiness due to minor UI changes.
Integrating E2E Tests with GitHub Actions
One of my most impactful contributions was automating E2E tests in the CI/CD pipeline using GitHub Actions. This ensures tests run with every push or pull request, catching issues early.
Here’s an example of a workflow I’ve used:
name: CI
on:
push:
branches:
- main
pull_request:
branches:
- main
jobs:
e2e:
runs-on: ubuntu-latest
steps:
- name: Checkout code
uses: actions/checkout@v2
- name: Set up Node.js
uses: actions/setup-node@v2
with:
node-version: '20'
- name: Install dependencies
run: npm install
- name: Run E2E Tests
run: npm run test:e2e
This workflow has helped maintain code quality while fostering a collaborative culture of continuous improvement.
Reducing Flakiness in Tests
Flaky tests can be a nightmare. I've spent a good part of my career dealing with them, and here are some strategies that worked for me:
Avoid Overlapping Tests: Isolate execution contexts using before and after hooks to set up and tear down test data.
Keep Tests Small and Focused: Testing a single functionality per test simplifies debugging and reduces complexity.
Regular Reviews: Periodically refactor flaky tests and align them with current application behavior.
Example:
cy.intercept('POST', '/api/checkout', { statusCode: 200, body: { order: '12345' } });
cy.get('[data-testid="checkout-button"]').click();
cy.get('[data-testid="order-confirmation"]').should('contain', 'Order 12345');
Stubbing network requests like this has been key in controlling external dependencies and reducing test failures.
By implementing these practices, I’ve significantly improved test reliability and maintainability in my projects. While advanced E2E testing requires balancing real-world interactions with stable test design, these lessons have been invaluable in my journey. I hope they help you too!
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