1. BIT 142:Programming & Data Structures in C#

2. What is Unit Testing? 2

3. 3 Unit Testing (Definition) “To write test cases for every non-trivial function or method in the module so that each test case is [as] separate from the others [as] possible.” www.discovercomputers.info/ComputerS ecurity/glossary.html www.discovercomputers.info/ComputerS ecurity/glossary.html

4. 4 Example Function To Test public bool isPrime( int num) { /*implementation omitted*/ } Definition of a prime number: –“A prime number (or a prime) is a natural number which has exactly two distinct natural number divisors: 1 and itself.” (Wikipedia)natural numberdivisors1 “The number 1 is by definition not a prime number”by definition not a prime number

5. 5 Example Unit Tests public bool isPrime( int num) { /*implementation omitted*/ } Test with: –small primes (2, 3, 5, 7, 11) –large primes –non-primes (1, 4, 9, 12, 11*17) –zero –negative numbers

6. Using NUnit 6

7. 7 What is NUnit? A free, open-source framework to help people create their own unit tests.

8. 8 NUnit’s Goal(s): Make it quick and easy to create unit tests, and to run those tests, and to get a list of which tests passed/failed.

9. How do I Use NUnit? For this class, you will NOT be required to create your own Unit Tests. You ARE required to write software that passes tests that are provided to you, by the teacher 9

10. How do I Use NUnit? You will download a starter project, which includes all the NUnit materials A quick example of how this all will work will follow this slide 10

11. 11 Demo: Quick walkthrough of how to use this –( GUI, Normal console, grade gen)

12. 12 Demo: Things you’ll need / find useful: –To select which project will be run: Right-click on a PROJECT, then select "Set Startup Project" –Edit  Find And Replace  Find In Files This will let you search ALL files for a particular string –How to get VS to comment/uncomment a block

13. 13 Workflow Student Workflow: –Download starter project –Examine first exercise, in Word.DOC Figure out which tests are used in the exercise Run tests, figure out which ones have failed Write code to make one (or more) tests pass –Repeat until all tests pass Repeat until all exercises done –DELETE DIRECTORIES ON NEXT SLIDE!!! –Hand in PCEs

14. 14 Submitting Your Work Delete the directory named DELETE_THIS_and_bin_and_obj_folders DELETE bin AND obj directories!!!

15. 15 Workflow Instructor workflow: –Run tests to get basic grade –Double-check code –Grade for feedback/ stuff that’s not auto- graded –Finalize grade & email gradesheets

16. BIT 142: Intermediate Programming16 Select “01_PCE_Test_Runner” as startup project –Make sure that in RunTests.cs, the line int doThis = RUN_TEST_IN_GUI; is uncommented –Run in VS, then click the ‘Run’ button in Nunit –NUnit should auto-reload the code when you recompile Details: GUI Test Runner 16

17. BIT 142: Intermediate Programming17 Be careful about which test(s) you’ve selected Note the ‘Text Output' tab –Especially for the BubbleSort exercise –Since the BubbleSort uses randomly generated arrays, you may not get the same array twice Details: GUI Test Runner 17

18. 18 Details: Normal Console Program Select “03_PCE_StudentCode” as startup project & run like normal The 'split file' thing: –Student_Answers.cs contains the code you will write, INCLUDING main!!

19. 19 Details: Normal Console Program Because the test code is in another project, you MUST make your classes PUBLIC in the StudentCode project This will either have been done for you, or else we’ll cover how to create your own classes in C#

20. BIT 142: Intermediate Programming20 Select “PCE_Test_Runner” as startup project –Make sure that in RunTests.cs, the line int doThis = RUN_TESTS_UNDER_DEBUGGER; is uncommented –Put a breakpoint in the test (or your code) –Run in VS you MUST choose Debug  Start Debugging –Useful features: Step, Step Into, Step Out Watch windows Details: Using The Debugger 20

21. BIT 142: Intermediate Programming21 Select “PCE_Test_Runner” as startup project –Make sure that in RunTests.cs, the line int doThis = PRODUCE_GRADESHEET; is uncommented –Run in VS –Everything should run, and the gradesheet should pop up in a web browser Details: Generating A Gradesheet 21

22. BIT 142: Intermediate Programming22 Note about grading output: –Not all tests that you can see in the GUI are graded –Failed tests are big, but passed tests are kinda small & on the bottom Details: Generating A Gradesheet 22

23. BIT 142: Intermediate Programming23 Note that compromising the system in any way will get you a zero –Hacking/changing/disabling tests –WRITING CODE TO PASS A TEST, DESPITE NOT ACCOMPLISHING IT’S REAL GOAL Ex: A ‘FindInArray’ method that just asks “Did I get asked to find the value 8? If so, return true”, so that it passes the test which asks “Is 8 in the array?” Details: Generating A Gradesheet 23

24. BIT 142: Intermediate Programming24 Note about grading output: –Not all tests that you can see in the GUI are graded –Failed tests are big, but passed tests are kinda small & on the bottom Details: Generating A Gradesheet 24

25. BIT 142: Intermediate Programming25 Located in the 02_PCE_ForTests project, inside the PCE_Test.cs file You should never need to change or modify these –We’ll go through them now, briefly, in order to make sure you’ve gotten a quick overview of how the NUnit tests work. –If you need to disable a test, you can just comment the whole method out, and the rest of the system *should* just work Details: NUnit tests 25

26. Understanding The NUnit Tests Attributes: –[Test] Specifies that test will be automatically called by NUnit. How the name shows up in the GUI 26

27. Understanding The NUnit Tests Attributes to ignore: –[Category] – ignore this –[TestFixture], [TimeOut], [Description] – ignore these Point out that the class to be tested MUST be public!! 27

28. Understanding The NUnit Tests Execution of a test: –Just like normal, it will be top to bottom –If the function crashes (or throws exception), then the crash will be caught, prevented (normally), and the test will fail –We can also tell NUnit to check that certain things are true at certain points, and fail if they’re not true 28

29. Understanding The NUnit Tests Assert.That( false, “message” ); –What this does 29

30. Understanding The NUnit Tests bool correctAnswer = false; Assert.That(correctAnswer, “message” ); 30

31. Understanding The NUnit Tests int num = 10; Assert.That( num == 12, “message”); 31

32. Understanding The NUnit Tests “Message” can work like Console.WriteLine: int num = 10; Assert.That( num == 12, “num={0} isn’t what we expected”, num); 32

33. Understanding The NUnit Tests More Attributes: –[Values()] – on a parameter 33

34. Understanding The NUnit Tests More Attributes: –[TestCase] 34

35. Understanding The NUnit Tests Console stuff: –Stealing Console.In –Capturing Console.Out Importance of the ‘fuzzy’ string comparison 35

36. Exercises: Drop existing, working code into a unit test, and watch the tests work –Look at a couple of simple tests –Go through & fiddle with test code, in order to learn it 36