UI testing: Balancing Coverage and Cost in Software Quality Assurance
Tags: testing, javascript, ui
Published: 2024-04-03 15:15:19

#### This post is part of a series on [testing strategy](https://dev.to/apssouza22/we-are-testing-software-wrongly-and-it-costs-a-lot-of-money-23o5), where I cover an end-to-end testing approach for web applications. Check it out!

In the quest for creating a resilient and user-friendly application, UI testing stands as a critical component of the software testing strategy. It ensures that users experience the application as intended and that the interface responds correctly to user interactions. However, an effective UI testing strategy is not just about coverage; it's about smart investment in the types of tests that provide the best return on investment. This post explores the strategic approach to UI testing, emphasizing integration testing and judicious use of end-to-end (E2E) tests.


While unit tests serve as the bedrock of a stable codebase, investing more heavily in integration tests can often yield greater dividends. Integration tests offer insights into how well different parts of the application work together, providing a closer approximation of real-world usage. For a robust testing suite, the focus should shift towards these integration tests, which effectively capture the interactions within the application.

E2E UI testing, particularly with tools like Cypress, is invaluable for verifying critical user journeys. However, these tests can be costly to run and maintain due to their complexity and the overhead involved in simulating the full range of user interactions. Given this, it’s prudent to reserve E2E UI tests for the most critical areas of your application—those user paths that are essential for the operation and revenue generation, such as checkout flows in an e-commerce app.

For integration tests, Jest emerges as an efficient and effective tool, particularly within the JavaScript and React ecosystems. Jest is well-suited for testing the interactions between components, verifying that they coalesce seamlessly to form a cohesive user experience.

In the context of a React application, where components range from simple to complex and are interdependent, integration testing verifies their combined functionality. Is important to not that the backend is not included in the integration tests, and therefore should be mocked.

Take, for instance, a to-do list application. Integration tests play a vital role in ensuring that components such as ListItem, ListItemAction, ListGroup, and TodoListView perform harmoniously. These tests would cover scenarios like adding a new task, marking a task as complete, editing an existing item, or removing it—simulating the user's perspective and actions.

In conclusion, the strategy of prioritizing integration testing over unit testing, while selectively applying E2E UI tests, aligns the development process with the ultimate goal of delivering a quality user experience. By utilizing tools like Jest for integration testing, and reserving tools like Cypress for the most critical paths, teams can maintain an effective balance between test coverage, execution cost, and maintenance overhead.