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Beyond Bug Catching

· 6 min read
Pere Pages
Developer working with bugs

The following article ("Stop testing your code!") made me think about the benefits of testing beyond Bug Cacthing.

Diving into the world of tests reveals a multitude of benefits beyond the obvious ones (like ensuring functionality integrity and catching bugs early). Let's break down some of these benefits and then touch upon common mistakes that can undermine these advantages.

Benefits of Writing Tests Beyond Bug Catching​

  1. Promotes Design of Clean Abstractions: Writing tests often necessitates the use of interfaces or abstract classes to mock or stub dependencies. This is a direct application of the Dependency Inversion Principle, leading to cleaner, more maintainable code.

  2. Encourages Modular Code: To make your code testable, you're pushed towards making it modular. This means breaking down your application into smaller, independent pieces that can be tested in isolation, enhancing code readability and reusability.

  3. Defines Use Cases Clearly: Tests, especially behavior-driven development (BDD) tests, can serve as a form of documentation. They clearly outline what the application is supposed to do from a user's perspective, making it easier for new developers to understand the intended functionality.

  4. Serves as Documentation: Well-written tests can serve as excellent documentation for your codebase. They provide a live demonstration of how your functions or components are expected to be used, making it easier for others to understand your code.

A part from the obvious​

  1. Improves Code Quality: Regular testing can lead to higher code quality by encouraging the writing of clean, efficient code that not only meets the current requirements but is also easier to maintain and extend over time.

  2. Facilitates Refactoring: With a comprehensive test suite, developers can refactor code with confidence. Tests will immediately catch any regressions or unintended side effects, ensuring that improvements or optimizations don't break existing functionality.

  3. Enhances Developer Confidence: Knowing that your codebase has a solid suite of tests provides a safety net that boosts confidence when making changes or adding new features. This can lead to a more innovative and bold approach to development.

Common Mistakes in Writing Tests​

However, there are common pitfalls that can detract from these benefits if not carefully avoided:

  1. Testing Implementation Details / Lack of Abstractions: Tests should focus on the behavior of the code, not how it's implemented. Testing implementation details can lead to brittle tests that break with any refactoring, even if functionality remains correct.

  2. Overusing Mocks: While mocking is useful for isolating units of code, overuse can lead to tests that are too detached from the real-world scenarios they're supposed to emulate, potentially missing important integration issues.

  3. Ignoring Test Readability: Tests act as documentation, so making them readable and understandable is vital. Neglecting this can lead to a maintenance nightmare where tests exist but are too cryptic to be useful.

The Page Object Model (POM)​

The Page Object Model (POM) is a design pattern widely used in web application testing, particularly for automated end-to-end tests. It's designed to enhance test maintenance and reduce code duplication.

The core idea

The core behind POM is to create an abstraction layer between the test scripts and the web pages to simplify test script development and improve maintainability.

The Page Object Model (POM)

Key Concepts of Page Object Model​

  • Page Objects: Each web page in the application is represented as a class, known as a "Page Object." This class encapsulates the page's structure and behaviors, offering methods that simulate user interactions on that page, like clicking a button or entering text into a form field.

  • Encapsulation of Elements: Within each Page Object, web elements (like buttons, input fields, and links) are defined as private member variables. Actions on these elements are exposed through public methods that perform operations, such as click or setText, abstracting away the direct interaction with the UI elements.

  • Method Chaining: Page Objects often return the instance of the same page or another page object after performing an action, facilitating method chaining in test scripts. This makes the tests easier to read and write.

How POM Helps with Abstractions​

  1. Separation of Concerns: By separating the page's UI structure and the test logic, POM makes tests cleaner and more focused on the workflow rather than UI specifics. This separation allows developers to modify the test behavior without touching the UI definitions and vice versa.

  2. Reusability: Since Page Objects encapsulate operations on a web page, these operations can be reused across multiple test cases. This not only reduces code duplication but also centralizes changes to element locators or interactions in one place.

  3. Maintainability: When the UI changes, updates are made in the Page Objects, not in the tests themselves. This significantly reduces the effort needed to maintain tests, especially in large suites where the same page elements are interacted with multiple times across tests.

  4. Readability: Tests written with POM tend to be more readable, as they abstract away the boilerplate of interacting with UI elements. The tests can read more like a description of the workflow, making it easier for new developers or testers to understand what the test is supposed to do.

  5. Reduced Flakiness: By centralizing the interaction with web elements, POM facilitates the implementation of consistent waiting strategies and error handling, which can reduce the flakiness of tests due to timing issues or intermittent failures.

Implementing POM​

Implementing the Page Object Model involves creating a class for each page that will be interacted with during testing. These classes contain methods that represent the functionalities of the page, abstracting the details of UI interactions. Test scripts then use these methods to perform actions in the application, benefiting from the abstraction layer that POM provides.

Overall, the Page Object Model is a powerful pattern for organizing test code in a way that promotes readability, maintainability, and reusability, making it an essential tool for any team serious about testing their web applications effectively.

A part from the obvious​

  1. Insufficient Coverage: Focusing too much on one area of the codebase (like the happy path) and neglecting others (like error handling) can give a false sense of security. Comprehensive coverage is crucial.

  2. Not Running Tests Regularly: Tests only provide benefits if they're run frequently. Not integrating tests into your development workflow, such as part of a CI/CD pipeline, misses out on the continuous feedback loop they provide.

  3. Writing Flaky Tests: Tests that sometimes pass and sometimes fail without any changes to the code (flaky tests) can erode trust in the testing suite and waste valuable developer time.