CSC307_L99_TDD.pdf

Transcript

1. Dr. Javier Gonzalez-Sanchez javiergs@calpoly.edu www.javiergs.info o ffi ce: 14 -227 CSC 305 Individual Software Design and Development Lecture 17. Test-Driven Development
2. 2 Testing Matters • Softw a re bugs a re expensive • M a nu a l testing does not sc a le • Regression issues a ppe a r frequently • Tests provide con f idence during ref a ctoring • Softw a re engineering relies on a utom a tion
3. 3 Test-Driven Development (TDD) • Tests a re written before implement a tion • Tests a ct a s "execut a ble requirements" • Focus on beh a vior a nd correctness • Encour a ges modul a r a nd m a int a in a ble design
4. 4 Process • Write a f a iling test • Implement minim a l code to p a ss • Improve design s a fely (ref a ctor) • Repe a t continuously during development
5. We need a library JUnit
6. 6 JUnit Basics • JUnit is the st a nd a rd J a v a testing fr a mework • Tests a re written a s J a v a methods • Assertions verify expected beh a vior • Tests should be isol a ted a nd repe a t a ble @Test • Set up your objects • Execute behavior • Assert // assertEquals(expected, // actual) // assertTrue(condition) // assertThrows(exception, code)
7. 7 Maven • src/m a in/j a v a → Applic a tion code • src/test/j a v a → Test code • pom.xml → Dependencies a nd build con f igur a tion • mvn test → Execute a utom a ted tests • Maven automatically discovers test classes • JUnit tests execute during the build process • Builds fail if tests fail
8. 8 Blueprint
9. 9 1. Interfaces • Interf a ces de f ine expected beh a vior • Developers implement concrete cl a sses • Tests v a lid a te correctness a utom a tic a lly
10. 10 1. Example
11. 11 2. Test • Cre a te objects • Beh a vior • Assert
12. 12 3. Test
13. 13 3. Implementation • Beh a vior
14. 14 3. Implementation
15. 15 Common Mistakes • H a rdcoding outputs • L a rge complex test methods • Not underst a nding requirements • Poor Git commit pr a ctices
16. Continuous Integration
17. 17 Continuous Integration (CI) • Autom a tic a lly builds a nd tests softw a re • Triggered on every commit or pull request • Detects problems e a rly
18. 18 GitHub Actions • GitHub Actions a utom a tes work f lows • Runs M a ven tests in the cloud • Provides p a ss/f a il feedb a ck • Integr a ted directly with GitHub repositories
19. 19 GitHub Actions
20. 20 Questions
21. Lab.
22. 22 Let’s Work (Individual Work Today) :: CSC 305 https://classroom.github.com/a/AVj9eSpy
23. CSC 307 Introduction to Software Engineering Javier Gonzalez-Sanchez, Ph.D. javiergs@calpoly.edu Winter 2026 Copyright. These slides can only be used as study material for the class CSC307 at Cal Poly. They cannot be distributed or used for another purpose.