dotnet-testing

name	dotnet-testing
description	.NET testing patterns for ContosoUniversity using xUnit, Moq, and WebApplicationFactory. Covers unit tests, integration tests, test infrastructure, mocking, and naming conventions.

.NET Testing Patterns

Testing patterns and infrastructure for ASP.NET Core applications using xUnit, Moq, and WebApplicationFactory.

Test Naming Convention

Use MethodName_Condition_ExpectedResult for all test methods:

[Fact]
public async Task GetByIdAsync_ValidId_ReturnsStudent()

[Fact]
public async Task Details_NullId_ReturnsNotFound()

[Theory]
[InlineData("")]
[InlineData(null)]
public async Task Create_EmptyLastName_FailsValidation(string? lastName)

Unit Test Pattern

public class StudentsControllerTests
{
    private readonly Mock<IRepository<Student>> _mockRepo;
    private readonly StudentsController _controller;

    public StudentsControllerTests()
    {
        _mockRepo = new Mock<IRepository<Student>>();
        _controller = new StudentsController(_mockRepo.Object);
    }

    [Fact]
    public async Task Index_WithStudents_ReturnsViewWithStudentList()
    {
        // Arrange
        var students = new List<Student>
        {
            new() { ID = 1, FirstMidName = "Carson", LastName = "Alexander" }
        };
        _mockRepo.Setup(r => r.GetAllAsync()).ReturnsAsync(students);

        // Act
        var result = await _controller.Index();

        // Assert
        var viewResult = Assert.IsType<ViewResult>(result);
        var model = Assert.IsAssignableFrom<IEnumerable<Student>>(viewResult.ViewData.Model);
        Assert.Single(model);
    }
}

Integration Test Pattern

public class StudentIntegrationTests : IClassFixture<CustomWebApplicationFactory>
{
    private readonly HttpClient _client;

    public StudentIntegrationTests(CustomWebApplicationFactory factory)
    {
        _client = factory.CreateClient();
    }

    [Fact]
    public async Task GetStudents_ReturnsSuccessAndHtml()
    {
        var response = await _client.GetAsync("/Students");
        response.EnsureSuccessStatusCode();
    }
}

Edge Cases to Always Test

Category	Examples
Null inputs	null ID, null model
Empty collections	No students in database
Invalid IDs	0, -1, non-existent
Validation failures	Missing required fields
Database errors	Repository throws exception