Test Driven Development and Testing Private Methods using JUnit

1. Test Driven Developmentand Testing Private Methods using JUnit By: Taylor Helsper

2. Outline • Introduction • Test Driven Development • JUnit • Testing Private Methods • TDD Example • Conclusion

3. Introduction • What is this lecture? • Part of a CSE 4000 Independent Study Course • “Practical Issues in Software Engineering” • What’s the point? • To provide practical information to students in Software Engineering topics Note: The products discussed in this presentation are examples used for teaching purposes and are not endorsements of the products.

4. Outline • Introduction • Test Driven Development • JUnit • Testing Private Methods • TDD Example • Conclusion

5. Test Driven Development • What is it? • Development/Testing process where tests are generated before the development • Development is completed based on the tests

6. Test Driven Development • Why is it useful? • Distinct Steps • Good Metrics • Ensures Completion Based on Requirements/Design

7. Test Driven Development • Why is it useful? • Only necessary features are implemented • Short Development Lifecycle • Easy to Accommodate Changes

8. Test Driven Development • Steps • Write tests based on design / requirements • Write code • Run tests • Repeat until all tests pass

9. Test Driven Development http://en.wikipedia.org/wiki/Test-driven_development

10. Outline • Introduction • Test Driven Development • JUnit • Testing Private Methods • TDD Example • Conclusion

11. JUnit • What is it? • JUnit is a testing framework for Java • It allows programmers to write test cases for Java classes

12. JUnit • Why use it? • Repeatability • Metrics / Measurement • Easy Integration

13. JUnit Examples • A JUnit Test Case

14. JUnit Examples • JUnit Before/ After

15. Outline • Introduction • Test Driven Development • JUnit • Testing Private Methods • TDD Example • Conclusion

16. Testing Private Methods • Why? • Better Tests • Higher Probability Errors are Found • Meet Regulations • Testing Standards • Code Coverage

17. Testing Private Methods • How? • Use Reflection • Java classes know info about themselves • Functions • Variables

18. Testing Private Methods • Java Example • Get Private Access

19. Testing Private Methods • Java Example • Test Private Method

20. Outline • Introduction • Test Driven Development • JUnit • TDD Example • Conclusion

21. TDD Example • Math Class for a Calculator Program • Steps • Generate Tests • Code • Run Tests • Repeat

22. Conclusion • Test Driven Development is important to understand • TDD is useful in many circumstances • TDD • Saves Money • Is Agile • Offers Good Metrics

23. References • Junit - http://www.junit.org/ • Netbeans – http://netbeans.org/ • JUnit Examples - http://junit.sourceforge.net/doc/cookbook/cookbook.htm • MSU Classes and work experience • Stack Overflow for Reflection Code - http://stackoverflow.com/questions/34571/whats-the-best-way-of-unit-testing-private-methods • Real’s How To for Reflection Code - http://www.rgagnon.com/javadetails/java-0031.html • “Subverting Java Access Protection for Unit Testing” by Ross Burton. 11/12/2003. onjava.com.

24. Questions?