Test Driven Development
- 1. Test Driven Development Dr. Davut Çulha
- 2. Test-driven Development (TDD) • Test-driven development (TDD) is a software development process that employs very short development cycle: – Testing – Coding – Refactoring • TDD = Test-first Programming + Refactoring. – Test-first programming is used in XP.
- 3. Test-driven Development (TDD) • TDD substantially reduces the incidence of defects. • It helps to improve the design of coding. • It minimizes the usage of debuggers.
- 4. Write Test Code • At each cycle of TDD, each new feature begins with writing a test. • If the feature is not very small, only a very small part of it is taken as a feature. This rule is applied for the rest of the initial feature. • After writing the test, execute it. It will fail. If it does not fail, repeat the process until failure. • Test codes should not be dependent to each other.
- 5. Write Some Code • Before coding actual feature, you should have taken the failure for the test. • Write some code which is just enough to pass the test. In other words, the failure will not be taken.
- 6. Refactor • Remove duplications. • Improve your code quality. • Use good naming. • Increase readibility. • Modularize the codes. • Use design patterns. • Do not change the external behaviour of the code. Change only the internal behaviour of the code to get technical excellence.
- 7. Reversible Changes • If the new feature addition takes a complex error, go to the last stable state. • Implement the same feature from the beginning. • Instead of using debugging and solving the problem, use reversible changes property of TDD. • Every change should be reversible. Start from the last stable state.
- 8. Documentation • Every test code is a kind of documentation. • It describes the interface of the actual coding. • Every test code is a sample program to investigate the actual program.
- 9. Code Base • In addition to actual codes, there are test codes. • The test codes should also be managed carefully. • The test codes should be kept as simple as you can like the actual codes.