Intro to Test-Driven Development in Go - Denise Yu

Step-by-Step Tutorial: Intro to Test-Driven Development in Go

Part 1: Understanding Test-Driven Development (TDD) in Go

1. What is Test-Driven Development (TDD)?

   • TDD is a software development practice that uses automated testing to create short feedback loops guiding the development of source code.
   • The core principle of TDD involves the steps: red, green, refactor.
     • Red: Write a failing test first.
     • Green: Modify the source code to pass the test.
     • Refactor: Improve the code while keeping all tests passing.

2. Types of Tests:

   • The testing pyramid suggests three levels of testing:
     • Unit Tests: Cover small code pieces, fast to develop and run.
     • Integration Tests: Check interactions between units.
     • End-to-End Tests: Validate the entire system, slower and more expensive.

Part 2: Implementing Test-Driven Development in Go

3. Using Go Test for TDD:

   • Utilize go test, the lightweight test runner in Go, to run tests.
   • Follow the TDD workflow: red (failing test), green (make the test pass), refactor (improve code).

4. Example: Implementing a Greeting Logic:

   • Write a test to greet users visiting a website.
   • Run go test to see the failing test.
   • Implement the code to pass the test (slime it if needed).
   • Refactor the code to improve readability and maintainability.

5. Extending Test Cases:

   • Introduce test groupings for multiple test cases.
   • Update source code to handle different inputs effectively.
   • Ensure all tests pass before moving on.

Part 3: Benefits of Test-Driven Development in Software Design

6. Improving Software Design with TDD:

   • TDD helps in designing modular and verifiable software.
   • Use failing tests to drive interface design and build verifiable boundaries.
   • Implement fake interfaces for testing flexibility and focus on individual modules.

7. Injecting Dependencies for Better Design:

   • Inject dependencies like loggers or configurations for explicit inputs and outputs.
   • Consider injecting global state changes to improve testability and maintainability.

8. Utilizing Libraries for TDD:

   • Explore libraries like Counterfeiter for generating fake implementations.
   • Use tools like quickly cover to guide behavior-driven design and improve code quality.

By following these steps and principles of Test-Driven Development in Go, you can enhance software design, ensure code reliability, and streamline the development process effectively.