TDD and BDD Overview

Test-driven development (TDD) is a software development approach where you write tests for your code before you actually write the code itself.

Behavior-driven development (BDD) is a software development approach that focuses on describing software behavior from the perspective of the user or stakeholder.

TDD follows a cycle of 'Red, Green, Refactor'. This means you first write a test that fails (Red), then write the code to make the test pass (Green), and finally refactor the code for better structure and clarity without changing its functionality.

The fear of introducing bugs or breaking existing functionality when making code modifications.

The fear of modifying existing code can be overcome by adopting a mindset of fearless competence, practicing incremental changes, creating a safe testing environment, and involving peers in code reviews and pair programming.

A metaphorical button that allows you to quickly clean and improve code without worrying about breaking anything.

Used to create objects with specific states or configurations, simplifying object creation.

Simple implementations of interfaces or classes used to mimic the behavior of real components.

Objects that record interactions, verifying that methods are called with expected arguments.

Simplified objects with predefined responses to simulate real components.

Record method usage to verify interactions, such as the number of times a method was called.

A design pattern where dependencies are injected into a class, promoting flexibility and testability.

Ensuring that the system behaves as expected, verifying that the code does what it should.

Every line of code is executed during testing, aiming to identify all potential bugs.

Writing tests before code ensures code meets requirements and behaves as expected, leading to fewer bugs and higher quality code.

Tests written before code helps catch bugs early, reducing the time spent on debugging later.

The need to pass tests encourages developers to write simpler, modular, and maintainable code, leading to better software design.

Automated tests provide immediate feedback, helping developers catch issues quickly, leading to faster iterations and more agile development.

The iterative nature of TDD encourages continuous improvement, where code quality and design are constantly enhanced.

Writing thorough tests for complex scenarios like user interfaces or multi-threaded code can be challenging and require frequent updates if the system architecture changes.

For small or simple projects, the overhead of TDD might be unnecessary and the cost-benefit ratio might not be favorable.

A complete test suite might give a false sense of security, as not all bugs can be caught through automated tests. Tests must be well-designed and cover edge cases to be truly effective.