Preventing Bugs with Unit Testing Chapter 5 - Coder to Developer by Mike Gunderloy

1. Preventing Bugs with Unit Testing Chapter 5 - Coder to Developer by Mike Gunderloy Instructor : Dr.James Fawcett Presented by Priyaa Nachimuthu priyaa@syr.edu

2. Agenda • Types of Testing • Testing for Developers • Unit Testing • Using NUnit • Test – Driven Development • Refactoring • Unit Testing Summary

3. Types of Testing • Unit Testing – testing very small pieces of code • Integration Testing - code doesn't break someone else’s code • System Testing – exercising the entire application to make it fail • Stress Testing – push the limits of the application until it fails • Beta Testing – giving copies of the unfinished code to outside testers for feedback • Acceptance Testing – formal verification of requirements

4. Testing for Developers • Check out the module • Write the code for the next feature to be implemented • Write unit tests to test the feature • Ensure that the code passes the unit tests • Get the latest code for the entire application • Make sure the whole project passes the integration tests • Check in code and unit tests

5. Unit Testing • JUnit – by Erich Gamma and Kent Beck for Java development • NUnit – free, open source framework, a .Net unit testing tool.NUnitAddin,TestRunner for NUnit integrates NUnit with VS.Net.NUnitAsp supports NUnit testing of ASP. Net pages. ( http://nunit.org ) • csUnit – free, open-source implementation. Additional features, includes project wizards to build new testing projects easily and a UI with more information. ( http://csunit.org ) • HarnessIt - $199.Pluaggable test engine architecture. Easy testing of web and remote applications using the same tools as local windows applications.( www.unittesting.com/default.aspx ) • X-Unity - $129.VS.Net integration, a development kit for unit tests, and integration ( http://x-unity.miik.com.ua/ ) • .TEST - $900.Writes many unit tests for the user. Uses rules-based engine to ensure code correctness and allows the user to write custom tests.( www.parasoft.com/jsp/products/home.jsp?product=TestNet )

6. Using NUnit for Unit Testing • A simple test • Debugging NUnit tests • Testing an exception • Testing with mock objects

7. Test Driven Development • A new testing technique by advocates of Extreme Programming. • Introduction to TDD : “Test-Driven Development” by Kent Beck. • Two simple rules - Write a failing automated test before writing any code - Remove duplication

8. TDD – Plan of Action • Quickly add a test • Run all tests and see the new one fail • Make a little change • Run all tests and see them all succeed • Refactor to remove duplication

9. TDD in Action • Code Sample

10. Refactoring • Martin Fowler’s Refactoring : Improving the Design of the existing Code • The process of changing a software system in such a way that it doesn't alter the external behavior of the code yet improves its internal structure. • Refactoring patterns • Code Thrashing – developers with different ideas

11. Refactoring Tools • dotEasy – free ( www.doteasy.com.uy/ ) • The C# Refactoring Tool - $110 ( http://dotnetrefactoring.com/ ) • C# Refactory - $99 ( www.xtreme-simplicity.net/CSharpReFactory.html ) • FlyWheel - $449 ( www.velocitis.com/ )

12. Unit Testing Checklist • Write unit tests for all code • Don’t postpone the tests • Ensure that the code passes unit tests and integration tests before check-ins • Use automated tools such as NUnit • Check the tests and any other setup files into SCC • Consider using TDD for 100% coverage • Refactor code only when there are thorough set of tests for the code

13. Thank you!