Xunit Testing in C#

Overview

• Focus on creating xUnit test projects in C#
• Writing unit tests using Fact and Theory
• Utilizing assert methods in unit testing

Setting Up xUnit Test Project

1. Create xUnit Test Project

   • Use Visual Studio 2022
   • Search and select "xUnit Test Project" with C#
   • Name the project and solution as round-the-code.xunit
   • Choose .NET 8 Long-Term Support

2. Create Class Library for Testing

   • Right-click solution -> Add new project -> Search "Class Library"
   • Name it round-the-code.xunit-domethods
   • Rename class to NumberHelper
   • Add methods to test:
     • IsOddNumber: Checks if a number is odd using number % 2 == 1
     • IsEvenNumber: Checks if a number is even
     • RatingScore: Uses switch statements to rate scores:
       • Below 3: "bad"
       • 3 to less than 7: "okay"
       • 7 to less than 10: "great"
       • Default: "unknown"

Writing Unit Tests

1. Adding Test Classes

   • Add dependency of Class Library to Test Project
   • Create a new class NumberHelperFactTests

2. Writing Fact Tests

   • Example Tests:
     • IsOddNumber: Value 3 should return true
     • IsOddNumber: Value 6 should return false
     • IsEvenNumber: Value 3 should return false
     • IsEvenNumber: Value 6 should return true
   • Use Assert.True or Assert.False
   • Apply [Fact] attribute to each method

3. Writing Theory Tests

   • Create NumberHelperTheoryTests
   • Copy existing tests and modify:
     • Change [Fact] to [Theory]
     • Use [InlineData] to test multiple inputs
     • Examples:
       • Test odd numbers with inputs like 3, 5, 7
       • Test even numbers with inputs like 2, 4, 6

4. Testing Rating Scores

   • Use Assert.Equal and Assert.NotEqual
   • Examples:
     • RatingScore: Value 7 should return "great"
     • RatingScore: Value 7 should not return "bad"
   • Apply [Theory] with multiple [InlineData]

Debugging Tests

• Place breakpoints in tests
• Right-click -> Debug to stop at breakpoints
• Inspect parameter values during execution

Conclusion

• Xunit is crucial for testing code effectively
• Watch related videos to learn more about xUnit
• Thorough testing helps prevent bugs in projects