FreePascal/Lazarus Test-Driven Development (TDD) e FPCUnit

Unit testing in FreePascal and Lazarus uses FPCUnit to establish test structure, naming conventions, and SetUp/TearDown methods. You create deterministic, testable code by drafting strong assertions that verify business logic.

Mocks in FreePascal are created using ARC-aware interfaces to isolate units under test. This approach allows you to build interface-based fakes that safely substitute dependencies when following the Red-Green-Refactor cycle.

Starting TDD in Lazarus involves drafting a failing FPCUnit test for the system under test before writing any implementation. You then implement the minimal code required to pass the test and refactor for readability.

The Red-Green-Refactor cycle in FreePascal enforces writing failing FPCUnit tests before implementing business logic. This workflow ensures your code remains testable and encourages safe, mock-driven designs through structured iterations.

Using interfaces for mocking in FPCUnit is essential to support deterministic, testable code. ARC-aware interfaces allow you to create reliable fakes that isolate your units under test without breaking memory management.

FPCUnit tests fail when business logic is written before tests, breaking the TDD workflow. You must enforce test structure and strong assertions first, ensuring new features pass through the Red-Green-Refactor cycle.