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 Writing snippets of code that try to use methods (functions) from your program.  Each snippet should test one (and only one) function......by calling the function, then comparing what the function actually produced to what it was supposed to produce.  Running the test code thus verifies that (at least part of) your program is doing what it’s supposed to. 2

 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 number divisors1  “The number 1 is by definition not a prime number”by definition not a prime number 3

 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 4

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 A free, open-source framework to help people create their own unit tests for any.Net language ◦ We’ll use it for C#  Related to (“inspired by”) JUnit ◦ JUnit is for Java testing 6

 Make it quick and easy to create unit tests, and to run those tests, and to get a list of which tests passed/failed. 7

 For this class, you will NOT be required to create your own Unit Tests.  You ARE required to write software that passes tests. The tests are provided to you, by the teacher 8

 You will download a starter project, which includes all the NUnit materials  Extract the.ZIP 9

10  Open the Solution (.SLN) file ◦ Note multiple projects  There are three projects inside the starter solution: ◦ 01_PCE_Test_Runner  This contains all the (instructor-provided) code that handles running the tests.  This includes running the test in the GUI, and running the auto-grading logic ◦ 02_PCE_ForTests  This is where the units tests themselves are located ◦ 03_PCE_StudentCode  This is where YOUR CODE must be put Details: Solution Setup

 Ignore anything except the RunTests.cs ◦ You can set the ‘mode’ here (you’ll see this later) 11

 This project contains all the tests  TestHelpers.cs contains stuff that multiple tests, across multiple assignments, make use of ◦ Input/output capturing code ◦ ‘Fuzzy’ comparisons 12

 PCE_Tests_To_Run.cs contains the actual tests – you’ll want to look in here for the details of each particular test. 13

 This is where YOUR CODE will be put. ◦ There will be just one file (Student_Answers.cs) ◦ Your code (that you will hand in) always goes into Student_Answers.cs 14

 If you want to experiment with a normal, console application, you do so by setting this project as the startup project, and then adding code to Main. 15

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 Make sure that “01_PCE_Test_Runner” is startup project ◦ Right-click on it, and “Set as startup project” if it’s not ◦ Make sure that in RunTests.cs, the line doThis = RUN_TEST_IN_GUI; is uncommented  In VS: Debug  Start (Without) Debugging ◦ (If either doesn’t work, prof!)  In the NUnit test runner: click ‘Run’ button ◦ Be careful about which test(s) you’ve selected 17

 NUnit should auto-reload your code when you recompile ◦ If it doesn’t, you can force it to reload: File  Reload Project or File  Reload Tests  You can then leave the test runner open, switch back to Visual Studio, change your program, and re-run your tests ◦ Without having to quit-and-restart NUnit 18

 Run the test(s) in the GUI  Get the name of a test that is failing 1. Edit  Find And Replace  Find In Files a) Type in the name of the failing test & go find it. 2. In 02_PCE_ForTests, in PCE_Tests_To_Run.cs find the test by hand 19

 Note the tabs at the bottom:  Errors And Failures: ◦ Lists out the exact error message when the test failed ◦ Tries to tell you where the failure occurred  Tests Not Run: ◦ This should never happen (unless there’s an error with the test)  Test Output: ◦ Anything you (or the test) Console.Writes will be displayed here 20

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 [Test] ◦ Specifies that test will be automatically called by NUnit. ◦ The GUI automatically finds this test, and gets the name to display in the GUI 22

 [Category] ◦ Used by the instructor to put a test into a grading category  [TestFixture], [TimeOut], [Description] ◦ Used to tell Nunit about tests 23

 NUnit ‘magically’ finds the tests to run ◦ Once the test starts, it runs just like normal code  We can tell NUnit to check that certain things are true at certain points, and fail if they’re not true ◦ This is done using the Assert.That command ◦ If the function crashes (or throws exception), then the crash will be caught, prevented (normally), and the test will fail 24

 Assert.That( false, “msg” );  What this does: ◦ If the first parameter (‘false’) is false, then the test will fail, with the message “msg”  Test: Basic_Fail in the Nunit_Demo project 25

bool correctAnswer = false; Assert.That(correctAnswer, “msg” );  This separates out the ‘is it correct?’ logic from the Assert statement  Notice that we can (and often will) use this pattern ◦ Test: Basic_Fail_2, Basic_Fail_3 26

 “Message” can work like Console.WriteLine:  int num = 10;  Assert.That( num == 12, “num={0} isn’t what we expected”, num);  Test: Basic_Console_WriteLine 27

 Typically, a test will call into your code, check the result, and then Assert that your answer is the same as the expected answer  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# 28

 This is the first ‘real’ unit test Call into your code Check the answer Pass (or fail) the test  Test: Basic_Unit_Test 29

 If you’re having trouble getting a test to pass, you can try adding print statements to your code, so that as the program runs, it tells you about what it’s doing 30

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 Certain tests may redirect input, output ◦ This means that they can ‘feed’ input to your code, and ‘capture’ the output that you produce  Capturing Console.Out in the Test ◦ Importance of the ‘fuzzy’ string comparison  Test-Supplied Console.In 32

 Using the TestHelpers software, the tests can capture output. ◦ This is in the TestHelpers.cs file ; you’re welcome to look at it, if you’re curious about how it works  Anything that you print (using Console.Write) can be captured  Test: Unit_Test_Console_WriteLine 33

 The TestHelpers software also provides for a number of helpful routines, including ‘fuzzy’ comparisons ◦ ‘Fuzzy’ for strings means case-insensitive, and without (too much) regard for blank spaces  Test: Unit_Test_Console_WriteLine_Fuzzy 34

 The test can also assemble a string, which will be used as the input to your code.  Whenever you call Console.Readline, you will read everything up to the next newline ◦ Enter key (Newline) in C#: \n  Example of input: ◦ “2\n3\nquit\n” is the same as typing 2 3 quit  Test: Unit_Test_Console_IO_Fuzzy 35

 public void Unit_Test_Values( [Values(-1, 0, 1, 10)]int valueToTry)  Tells NUnit to call this function four separate times: ◦ once with valueToTry set to -1 ◦ once with valueToTry set to 0, ◦ once with valueToTry set to 1 ◦ once with valueToTry set to 10  Test: Unit_Test_Values 36

 public void Unit_Test_Values_2( [Values(1, 10)]int a, [Values(2, 4)]int b)  Tells NUnit to call this function with ALL POSSIBLE COMBINATIONS OF a and b: ◦ a = 1, b = 2 ◦ a = 1, b = 4 ◦ a = 10, b = 2 ◦ a = 10, b = 4  Test: Unit_Test_Values_2 37

[TestCase( 1, 2)] [TestCase( 10, 4)] public void Unit_Test_TestCase(int a, int b)  Tells NUnit to call this function with EACH TestCase: ◦ a = 1, b = 2 ◦ a = 10, b = 4  Test: Unit_Test_TestCase 38

 Notice that before each test, the method marked with [Setup] will be run  In the example test, we’ll use this to initialize x to be 10, y to be 20, and ex5 to refer to an object  Test: Unit_Test_Setup 39

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 Not all tests that you can see in the GUI are neccessarily graded  Failed tests are big, but passed tests are kinda small & on the bottom 41

 Note that compromising the system in any way will get you a zero ◦ Cracking/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?” 42

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 Make sure that 03_PCE_StudentCode is the startup project ◦ Right-click on the PROJECT, and choose “Set as Startup Project” to make it the startup project  Put whatever code you want to into the main method. 44

 If you want, you can always create a new console solution, then copy your code into it. 45