Testing Setup and Runners

Level: Intermediate

ℹ️ What You'll Learn

• Create test projects
• Configure xUnit/NUnit
• Run tests in Visual Studio
• Test Explorer window
• Coverage analysis

Create Test Project

File → New Project → xUnit Test Project:

Project name: SMS.Tests
Location: C:\NexCoding\SMS\
Framework: .NET 8

Structure:

SMS.Tests/
├── SMS.Tests.csproj
├── UnitTest1.cs
├── Usings.cs
└── bin/obj/

Add Project Reference

Right-click SMS.Tests → Add Reference → SMS.Core

Now can test SMS.Core code.

Write First Test

File: StudentServiceTests.cs

using Xunit;
using SMS.Services;

public class StudentServiceTests
{
    [Fact]
    public void GetStudent_WithValidId_ReturnsStudent()
    {
        // Arrange
        var service = new StudentService();
        int studentId = 101;
        
        // Act
        var result = service.GetStudent(studentId);
        
        // Assert
        Assert.NotNull(result);
        Assert.Equal("Ravi Kumar", result.Name);
        Assert.Equal("10-A", result.ClassName);
    }

    [Theory]
    [InlineData(0)]
    [InlineData(-1)]
    public void GetStudent_WithInvalidId_ThrowsException(int id)
    {
        var service = new StudentService();
        Assert.Throws<ArgumentException>(() => service.GetStudent(id));
    }
}

Test Explorer

View → Test Explorer (or Ctrl + E, T):

SMS.Tests
├── ✓ GetStudent_WithValidId_ReturnsStudent (passed)
├── ✓ GetStudent_WithInvalidId_ThrowsException[0] (passed)
└── ✓ GetStudent_WithInvalidId_ThrowsException[-1] (passed)

Run tests:

• Run All: Ctrl + R, A
• Run Failed: Ctrl + R, F
• Run Selected: Select test → Ctrl + R, T

NUnit vs xUnit

xUnit (recommended):

[Fact]           // One test
[Theory]         // Multiple test cases
[InlineData(...)] // Inline test data

NUnit:

[Test]           // One test
[TestCase(...)]  // Multiple test cases
[Values(...)]    // Value parameters

Both work. Choose one per project.

Test Coverage

Analyze → Code Coverage → Measure Code Coverage:

StudentService.cs:
- GetStudent():  ✓ 100% covered
- GetStudents(): ✗ 60% covered (missing edge cases)
- DeleteStudent(): ✗ 0% covered (no tests)

Aim for 80%+ coverage.

Key Takeaways

• Create separate test project
• Test = Arrange, Act, Assert
• xUnit = cleaner syntax
• Test Explorer = run/debug tests
• Coverage = measure test completeness

💡 Testing Pro Tip

Write tests first (TDD), then implementation. Tests document expected behavior.

🤖Use AI to Learn Faster

Use ChatGPT, Claude, or Copilot to go deeper on Visual Studio Testing. Try these prompts:

• "How do I create a test project?"
• "What's the difference between Fact and Theory?"
• "Quiz me on testing"

💡 Tip: After reading this article, paste your own code into AI and ask "What could go wrong here and why?" — fastest way to find edge cases and deepen understanding.