Best E2E Automation Testing Practices

This article shares insights and best practices for end-to-end (E2E) testing based on my hands-on experience. I started with minimal knowledge in this field, but over time, I learned the importance of building robust, reliable tests. Facing challenges like flaky tests and unstable pipelines taught me valuable lessons. My goal here is to go beyond the basics and offer strategies that reduce test maintenance, improve stability, and enhance readability in complex projects.

Instead of reiterating what's already covered in official documentation, this guide focuses on practical techniques I've applied successfully in real-world projects. If you're new to E2E testing or want to deepen your understanding, I recommend exploring these resources alongside my experiences:

Official Cypress Best Practices Guide
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!