ITCamp 2013 - Florin Coros - Driving Your Team Towards Code Quality
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This document discusses the importance of code quality and driving teams towards good code quality through practices like writing good unit tests. It advocates for writing unit tests that are small, isolated, test only one thing, and are easy to implement. Having such unit tests helps enforce good design principles and patterns that lead to code that is more maintainable, extensible and reusable. It also discusses how continuous refactoring guided by unit tests can help reduce technical debt and keep code quality high over time.
ITCamp 2013 - Florin Coros - Driving Your Team Towards Code Quality
- 1. itcampro@ itcamp13# Premium conference on Microsoft technologies Driving Your Team Towards Code Quality Florin Coros www.rabs.ro [email protected] @florincoros www.florincoros.wordpress.com
- 2. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesHuge thanks to our sponsors!
- 3. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesAbout me RABS, Co-Founder ISDC, Software Architect @florincoros
- 4. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesInspired
- 5. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesWhy Code Quality?
- 6. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesChange Predictability - How much time to add this new small feature? - Hm… let’s see… so it is very similar with what we have, right? Hm… about 2 to 3 days I think...
- 7. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesChange Predictability crap…. I have to change much more than I thought … No way I can do this by tomorrow … I think I’m going to work on this 2 to 3 weeks maybe
- 8. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesIt works. Don’t touch it!
- 9. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesGood Design vs Bad Design http://martinfowler.com/bliki/DesignStaminaHypothesis.html
- 10. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesTechnical Debt
- 11. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesFunctions, Classes, Modules
- 12. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesDesigns 1 2 3 4 http://channel9.msdn.com/Events/TechEd/NorthAmerica/2010/ARC201
- 13. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesDesigns http://channel9.msdn.com/Events/TechEd/NorthAmerica/2010/ARC201
- 14. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesDesign Principles & Design Patterns
- 15. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesKnowledge vs Experience You learn the rules of chess in a few hours You become a good chess player after years of practicing You need to practice with strong opponents You need to go to tournaments to meet strong opponents You learn the rules of GO in a few minutes You become a good GO player after many years of practicing Same as at chess, but much more exercise is needed because it is more complex
- 16. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesAlternative: GOOD Unit Tests It is very small It can be written easily and runs quickly It’s readable, maintainable, trustworthy and fully automated It should run in isolation It should test ONE thing If it fails you should know exactly where the bug is
- 17. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesHow does GOOD UT get us there? OOD Principles SOLID DRY IoC & DI LowCoupling High Coherence …..… Design Patterns Composite Chain Of Responsibility Decorator ……. Can you TEST it? Good Enough GOOD Unit Tests Small In Isolation Test ONE Thing Easy to implement
- 18. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesGood Unit Tests - easy to write less than 5 minutes to implement few lines of code. Less than 10 -15 see from a glimpse what the test checks
- 19. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesGood Unit Tests - Run in Isolation Isolate the code under test from the rest of your system, by creating seams, to be able to plug fakes (stubs & mocks) which you can control in your test “There is no object-oriented problem that cannot be solved by adding a layer of indirection, except, of course, too many layers of indirection.”
- 20. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesGood Unit Test - test ONE thing Check only ONE thing in your tests. If the test fails you know exactly where the problem is. You do not need to do step-by-step debugging
- 21. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesGood Unit Tests - not integration tests B C f() g() h() h’() Depend on abstractions not on implementation details (DIP) Use IoC for instantiating objects, or Factory design patterns Visible dependencies for our classes Low coupling and high coherence Extensibility, Reusability (OCP) Design Patterns Integration tests: HIGH COSTS & LOW BENEFITS
- 22. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesGood Unit Tests - not integration tests Screen Keyboard translate() write() read() Depend on abstractions not on implementation details (DIP) Use IoC for instantiating objects, or Factory design patterns Visible dependencies for our classes Low coupling and high coherence Extensibility, Reusability (OCP) Design Patterns Integration tests: HIGH COSTS & LOW BENEFITS
- 23. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesGood Unit Tests - not integration tests IText Output IText Input translate() write() read() Depend on abstractions not on implementation details (DIP) Use IoC for instantiating objects, or Factory design patterns Visible dependencies for our classes Low coupling and high coherence Extensibility, Reusability (OCP) Design Patterns Integration tests: HIGH COSTS & LOW BENEFITS
- 24. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesEliminate circular dependencies A simple designed system cannot be large It has low coupling and high coherence
- 25. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesEliminate circular dependencies A system is large and too rigid to change if it has circular dependencies It has high coupling and low coherence
- 26. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesContinuous & Small Cycles CODE UNIT TEST REFACTOR Short cycles between unit test and production code Refactor in early stage, at lower costs Same principle for test first or for code first
- 27. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesCode Coverage History 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Infrastructure 30 35 40 41 60 70 70 75 75 76 79 78 80 68 70 71 65 71 65 70 68 CoreServices 60 75 80 81 78 80 81 78 75 81 89 78 75 80 68 75 80 78 81 79 80 Module 1 0 30 40 45 50 60 58 60 57 55 60 58 60 61 57 55 50 48 42 57 59 Module 2 50 60 65 70 68 67 75 77 75 74 73 75 77 75 73 75 72 74 75 77 75 0 10 20 30 40 50 60 70 80 90 100 %BlocksCovered
- 28. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesIs it easier? OOD Principles Design Patterns Can you TEST it? Reusability Extensibility Maintainability GOOD Unit Tests Bad Design Smells with Good Tests Code at wrong level of abstraction Class with more responsibilities Base classes depending on their derivates Artificial coupling Feature envy Polymorphism over if/else or switch/case Poor coherance Violates SOLID Should have used certain design pattern Test is difficult to understand. It is very large (more than 20 lines) Checks on more than ONE thing Does not run in isolation Are not following the naming conventions
- 29. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesHow to do it? Architecture App Software Infrastructure Vertical Slice Review Good UT Refactor WHOLE team is doing Good Unit Testing! Deliver Functionality Deliver Functionality Deliver Functionality Define code coverage targets
- 30. itcampro@ itcamp13# Premium conference on Microsoft technologies Architecture & Best PracticesThank you!