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

Agenda Introduction to Unit Testing Basic Examples with NUnit Why Unit Testing? Advanced Features (if we have time)

Code

Tests

Tests

Tests

Introduction to Unit Testing

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

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

NUnitMSTestMbUnitetc.

Testing FrameworkA set of code and tools to test existing codeTesting code is decorated with attributesTesting Framework uses Reflection to invoke testing code

Most tests either Pass or Fail

Demo – Array UtilThe task:A method has 2 input parameters:

A non empty, sorted array of integersAn integer

The output should be the closest number from the array to the input number.

"Closest" in terms of absolute valueTry to write it yourself!

Why Unit Testing?Unit Testing is a STANDARD

No need to manually test code by console applications

Accepted by Developers Expected by Developers

Fearlessly Change Implementation

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

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

I Can't Test That CodeMore than a single class is used

Even worse: Singletons are usedHardware boundaries:

System ClockHTTP RequestsFile Read/Write

Refactor!

Unit TestingMore code to test our codeUnit Testing Leads to:

Fearlessly Change ImplementationBetter Code / Better Design

If a class can't be tested – consider refactoring

Legacy code is code without tests

Resources

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

Thank You!