Unit Testing with NUnit introduces unit testing and the NUnit testing framework. It demonstrates writing basic tests for a method that finds the closest number in an array to a given input. The document emphasizes that unit testing leads to code that is easier to change and improve, as tests allow refactoring without breaking existing functionality. It also notes that code should be designed and structured to facilitate testing, and legacy code without tests is difficult to refactor safely.

1. Unit Testing with NUnitRon Kleinhttp://heblog.ronklein.co.il http://tinyurl.com/ronklein

2. AgendaIntroduction to Unit TestingBasic Examples with NUnitWhy Unit Testing?Advanced Features (if we have time)

3. Introduction to Unit TestingTestsTestsTestsCode

4. What's a Unit?Unit == class || methodUnit != classes.Count > 1

5. How to test?Manually? –possible, but not so friendlyAutomated Frameworks:NUnitMSTestMbUnitetc.

6. Testing FrameworkA set of code and tools to test existing codeTesting code is decorated with attributesTesting Framework uses Reflection to invoke testing codeMost tests either Passor Fail

7. Demo – Array UtilThe task:A method has 2 input parameters:A non empty, sorted array of integersAn integerThe output should be the closest number from the array to the input number."Closest" in terms of absolute valueTry to write it yourself!

8. Why Unit Testing?Unit Testing is a STANDARDNo need to manually test code by console applicationsAccepted by Developers Expected by DevelopersFearlessly Change Implementation

9. Why Unit Testing?Fearlessly Change Implementation(back to demo)

10. Why Unit Testing?Leads us to Better Code / Better DesignDemo: Greet example

11. I Can't Test That CodeMore than a single class is usedEven worse: Singletons are usedHardware boundaries:System ClockHTTP RequestsFile Read/WriteRefactor!

12. Unit TestingMore code to test our codeUnit Testing Leads to:Fearlessly Change ImplementationBetter Code / Better DesignIf a class can't be tested – consider refactoringLegacy code is code without tests

13. ResourcesNUnit: http://nunit.org/Moq: http://code.google.com/p/moq/

14. Thank You!