The document provides an overview of Test-Driven Development (TDD), describing it as a software development process where requirements are transformed into specific test cases that guide coding efforts. It outlines the historical context, principles of software craftsmanship, common development challenges, and the advantages of using TDD. Additionally, it includes a Lego workshop exercise that applies TDD in building a car, emphasizing the importance of refactoring and maintaining test coverage throughout the development process.

1. TDD
Test Driven Development
The best thing that has happened to software design
Arek Torczuk, ThoughtWorks

2. Definition
“Test-Driven Development (TDD) is a software development process that relies on the repetition of a very
short development cycle: requirements are turned into very specific test cases, then the software is
improved so that the tests pass.”
Wikipedia

3. History
● 1950’s: “Test First” approach discovered.
● 1998: Kent Beck (XP) rediscovers this principle.
● 2003: Beck coined the term TDD.

4. Software Craftsmanship Principles
● Not only working software, but also well-crafted software
● Not only responding to change,but also steadily adding value
● Not only individuals and interactions, but also a community of professionals
● Not only customer collaboration, but also productive partnerships
TDD helps support these principles.

5. Common Software Development Problems
● Difficulty in testing code
● Over-engineered solutions
● “While I’m working on this” syndrome
● Fear of refactoring

6. Advantages of TDD
● Maintaining a high standard of quality
● Building an optimal code coverage
● Emergent Design
● Clean Code, Testable Code
● Allows for refactoring
● Ultimately, go faster

7. The three laws of the TDD cycle
1. Write a failing test
2. Write just enough code to pass the test
3. Refactor

8. Workshop - Lego

9. Lego Workshop - Setup
● Goal: Use TDD to build a car
● Challenge: Implementation changes should not affect tests
● You are given:
● A bag of Legos
● One highlighter
● Two types of grid paper
● A list of requirements

10. Lego Workshop - Rules
● Draw your test first:
● Use the plate as a reference point.
● Add as few legos as possible to make your test pass.
● Make sure your test suite still passes before implementing the subsequent
requirement.

11. Requirement 1: Car must have a plate for the floor.
Large car (6 x 8) Small car (4 x 8)

12. Requirement 2: Body of the car must be one block high.
Large car (6 x 8) Small car (4 x 8)

13. Requirement 3: Car must have a steering wheel.
Large car (6 x 8) Small car (4 x 8)

14. Requirement 4: Car must accommodate one driver.
Large car (6 x 8) Small car (4 x 8)

15. Requirement 5: Car must have a windshield.
Large car (6 x 8) Small car (4 x 8)

16. Requirement 6: Car must have four wheels.
Large car (6 x 8) Small car (4 x 8)

17. Congratulations!!!
The customer is very happy with your
car!
You have obtained more budget to
continue building your car!!!

18. Refactoring
● You have to change your existing design to satisfy new customer requirements.
● Do not forget to update your tests if needed and make sure that they always pass!

19. Off to work we go!

20. New Requirements
● Requirement 7: Car must have a yellow decorative line on each side of the car.
● Requirement 8: Car must have a rear spoiler.

21. Final Product!

22. Exercise Review
● TDD eases refactoring:
○ Creates an optimal test coverage.
○ Increases confidence in the code.
○ Removes fear of change/ regression.
● Aim for one validation per test.
● Test the state after execution, not the implementation.

23. ???

24. References
Kent Beck explains that TDD has existed for longer than we think.
https://arialdomartini.wordpress.com/2012/07/20/you-wont-believe-how-old-tdd-is/
Kent Beck - Test Driven Development
https://www.amazon.ca/Test-Driven-Development-Kent-Beck/dp/0321146530
TDD: the best thing that has happened to software design
https://www.thoughtworks.com/pt/insights/blog/test-driven-development-best-thing-has-happened-software-design
Why TDD
https://builttoadapt.io/why-tdd-489fdcdda05e
Why TDD will change your developer life?
https://medium.com/@raphaelyoshiga/why-tdd-will-change-your-developer-life-b0bf234e15ac

25. Available Training Classes
● DevOps
● Clean Architecture
● TDD
● ATDD
● BDD
● Testable Code
● Clean Code
● SOLID Principles
● Automated Testing

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