Getting started with TDD

A short talk I use to present for people curious about understanding the basics of TDD

Transcript

1. Getting Started with Test Driven Development
2. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 2/24 HIGH LEVEL ARCHITECTURE
3. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 3/24 ABOUT PATKÓS CSABA
4. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 4/24 STRUCTURE PART 1 – About testing in general. PART 2 – Test Driven Development explained. PART 3 – A short live example.
5. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 5/24 AUTOMATED TESTING In software testing, test automation is the use of special software (separate from the software being tested) to control the execution of tests and the comparison of actual outcomes with predicted outcomes. Source Wikipedia
6. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 6/24 AUTOMATED TESTING TEST CODE PRODUCTION CODE
7. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 7/24 DIFFERENT TEST TYPES U N I T T E S T S M.T. E2E A.P.I. TESTS INTEGRATION TESTS COMPONENT TESTS
8. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 8/24 HIGH LEVEL ARCHITECTURE
9. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 9/24 MANUAL AND END-TO-END TESTS M ANUAL & E2E TEST BACKDOOR VERIFICATION FRONTDOOR VERIFICATION
10. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 10/24 A.P .I. TESTS A.P.I. TESTS A.P.I. TESTS X X X
11. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 11/24 INTEGRATION TESTS Business Logic INTEGRATION TESTS C C C C C
12. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 12/24 COMPONENT TESTS Business Logic C C C COMPONENT CLASS CLASS CLASS CLASS CLASS COM PONENT TESTS
13. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 13/24 UNIT TESTS Business Logic COMPONENT CLASS CLASS CLASS CLASS CLASS PUBLIC METHOD PUBLIC METHOD PR . ME. PR . ME. PR . ME. PR . ME. PR . ME. PR . ME. U N I T T E S T S
14. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 14/24 A SIMPLE UNIT TEST EXAMPLE Set Up Exercise Verify
15. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 15/24 WHAT ABOUT COMPLEX METHODS?
16. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 16/24 FROM CODE TO TEST AND BACK AGAIN COMPLICATED CODE IMPOSSIBLE TEST SIMPLE CODE EASY TESTING SIMPLE TESTS SIMPLE CODE
17. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 17/24 THE THREE LAWS OF TEST DRIVEN DEVELOPMENT 1.You are not allowed to write any production code unless it is to make a failing unit test pass. 2.You are not allowed to write any more of a unit test than is sufficient to fail; and compilation failures are failures. 3.You are not allowed to write any more production code than is sufficient to pass the one failing unit test. Robert C. Martin
18. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 18/24 THE THREE STAGED CYCLE OF TEST DRIVEN DEVELOPMENT R E D GREEN REFACTOR 1. Write Test 2. Fail the Test 3. Write Production Code 4. Pass the Test 5. Refactor both Test and Productin Code 6. Ensure Tests are Still Passing
19. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 19/24 IT'S TIME FOR A LIVE DEMO THE FIZZBUZZ EXERCISE https://en.wikipedia.org/wiki/Fizz_buzz
20. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 20/24 TESTING OBJECT COLLABORATION SmartCar Steering SpeedControl
21. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 21/24 TEST STUB We replace a real object with a test-specific object that feeds the desired indirect inputs into the system under test. Gerard Meszaros
22. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 22/24 TEST SPY We use a Test Double to capture the indirect output calls made to another component by the SUT for later verification by the test. Gerard Meszaros
23. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 23/24 TEST MOCK We replace an object on which the SUT depends on with a test-specific object that verifies it is being used correctly by the SUT. Gerard Meszaros
24. 2014 – Patkós Csaba / patkoscsaba@gmail.com / @PatkosCsaba / patkoscsaba.blogspot.com 24/24 TEST FAKE We replace a component that the SUT depends on with a much lighter-weight implementation. Gerard Meszaros