Unit Testing Skill - PortalEmpleo

Name: unit-testing
Rating: 76
Author: ricardoahumada

When to use this skill

Use this skill when creating unit tests for services and business logic in PortalEmpleo. This skill is automatically triggered when the user mentions:

•Unit tests
•xUnit
•Test cases
•Mocking with Moq
•FluentAssertions

Project Context

•Test Framework: xUnit
•Mocking: Moq
•Assertions: FluentAssertions
•Target: Service classes in Application layer
•Coverage Target: >= 80%

Test Class Structure

csharp

using PortalEmpleo.Application.Services;
using PortalEmpleo.Application.Services.DTOs;
using FluentAssertions;
using Moq;
using Xunit;

namespace PortalEmpleo.Tests.Services;

public class AuthServiceTests
{
    private readonly Mock<IUserRepository> _userRepositoryMock;
    private readonly Mock<IJwtService> _jwtServiceMock;
    private readonly Mock<IPasswordService> _passwordServiceMock;
    private readonly AuthService _authService;

    public AuthServiceTests()
    {
        _userRepositoryMock = new Mock<IUserRepository>();
        _jwtServiceMock = new Mock<IJwtService>();
        _passwordServiceMock = new Mock<IPasswordService>();
        _authService = new AuthService(
            _userRepositoryMock.Object,
            _jwtServiceMock.Object,
            _passwordServiceMock.Object);
    }
}

Test Method Pattern (AAA)

csharp

[Fact]
public async Task RegisterAsync_WithValidData_ReturnsAuthResult()
{
    // Arrange
    var registerDto = new RegisterDto
    {
        Email = "test@example.com",
        Password = "SecurePassword123!",
        Name = "Test User",
        BirthDate = new DateTime(1990, 1, 1)
    };

    var user = new User
    {
        Id = Guid.NewGuid(),
        Email = registerDto.Email,
        Name = registerDto.Name
    };

    _userRepositoryMock
        .Setup(r => r.GetByEmailAsync(registerDto.Email))
        .ReturnsAsync((User?)null);

    _userRepositoryMock
        .Setup(r => r.AddAsync(It.IsAny<User>()))
        .Callback<User>(u => u.Id = user.Id);

    _jwtServiceMock
        .Setup(j => j.GenerateAccessToken(It.IsAny<User>()))
        .Returns("access-token");

    _jwtServiceMock
        .Setup(j => j.GenerateRefreshToken(It.IsAny<User>()))
        .Returns("refresh-token");

    // Act
    var result = await _authService.RegisterAsync(registerDto);

    // Assert
    result.Should().NotBeNull();
    result.AccessToken.Should().Be("access-token");
    result.RefreshToken.Should().Be("refresh-token");
    _userRepositoryMock.Verify(r => r.AddAsync(It.IsAny<User>()), Times.Once);
}

Common Test Scenarios

Success Cases

csharp

[Fact]
public async Task LoginAsync_WithCorrectCredentials_ReturnsTokens()
{
    // Arrange
    var loginDto = new LoginDto
    {
        Email = "user@example.com",
        Password = "CorrectPassword123!"
    };

    var user = new User
    {
        Id = Guid.NewGuid(),
        Email = loginDto.Email,
        PasswordHash = "$2a$12$..."
    };

    _userRepositoryMock
        .Setup(r => r.GetByEmailAsync(loginDto.Email))
        .ReturnsAsync(user);

    _passwordServiceMock
        .Setup(p => p.VerifyPassword(loginDto.Password, user.PasswordHash))
        .Returns(true);

    _jwtServiceMock
        .Setup(j => j.GenerateAccessToken(user))
        .Returns("valid-token");

    // Act
    var result = await _authService.LoginAsync(loginDto);

    // Assert
    result.Should().NotBeNull();
    result.AccessToken.Should().Be("valid-token");
}

Failure Cases

csharp

[Fact]
public async Task LoginAsync_WithInvalidEmail_ReturnsNull()
{
    // Arrange
    var loginDto = new LoginDto
    {
        Email = "nonexistent@example.com",
        Password = "anypassword"
    };

    _userRepositoryMock
        .Setup(r => r.GetByEmailAsync(loginDto.Email))
        .ReturnsAsync((User?)null);

    // Act
    var result = await _authService.LoginAsync(loginDto);

    // Assert
    result.Should().BeNull();
    _jwtServiceMock.Verify(j => j.GenerateAccessToken(It.IsAny<User>()), Times.Never);
}

[Fact]
public async Task RegisterAsync_WithDuplicateEmail_ThrowsException()
{
    // Arrange
    var registerDto = new RegisterDto
    {
        Email = "existing@example.com",
        Password = "SecurePassword123!"
    };

    var existingUser = new User { Email = registerDto.Email };

    _userRepositoryMock
        .Setup(r => r.GetByEmailAsync(registerDto.Email))
        .ReturnsAsync(existingUser);

    // Act & Assert
    var action = () => _authService.RegisterAsync(registerDto);
    await action.Should().ThrowAsync<InvalidOperationException>();
}

Required Elements

1. Test Class

•Public class with Tests suffix
•Constructor with mock initialization
•IDisposable for cleanup (if needed)

2. Test Methods

•[Fact] or [Theory] attribute
•Descriptive name: MethodName_Scenario_ExpectedResult
•Arrange-Act-Assert structure
•Async support with Task return type

3. Mocking

•Mock<T> for dependencies
•Setup for return values
•Verify interactions with Times.Once/Times.Never

4. Assertions (FluentAssertions)

•Should().NotBeNull()
•Should().Be(expectedValue)
•Should().BeEquivalentTo()
•Should().ThrowAsync<T>()

Output Format

Generate:

•Complete test class file
•Multiple test methods per service
•Mock setup for dependencies
•FluentAssertions for assertions

Files to Write

•tests/PortalEmpleo.Tests/[Service]Tests.cs

Coverage Target

•Minimum 80% code coverage
•Test all public methods
•Include edge cases and error scenarios