the-biergarten-app/web/backend/Features/Features.Auth.Tests/Queries/LoginHandlerTests.cs

using Domain.Entities;
using Domain.Exceptions;
using Features.Auth.Commands.Login;
using Features.Auth.Dtos;
using Features.Auth.Repository;
using Features.Auth.Services;
using FluentAssertions;
using Infrastructure.PasswordHashing;
using Moq;

namespace Features.Auth.Tests.Queries;

public class LoginHandlerTests
{
    private readonly Mock<IAuthRepository> _authRepoMock;
    private readonly LoginHandler _handler;
    private readonly Mock<IPasswordInfrastructure> _passwordInfraMock;
    private readonly Mock<ITokenService> _tokenServiceMock;

    public LoginHandlerTests()
    {
        _authRepoMock = new Mock<IAuthRepository>();
        _passwordInfraMock = new Mock<IPasswordInfrastructure>();
        _tokenServiceMock = new Mock<ITokenService>();
        _handler = new LoginHandler(
            _authRepoMock.Object,
            _passwordInfraMock.Object,
            _tokenServiceMock.Object
        );
    }

    [Fact]
    public async Task Handle_WithValidData_ReturnsPayloadWithMatchingUsername()
    {
        const string username = "CogitoErgoSum";
        Guid userAccountId = Guid.NewGuid();

        UserAccount userAccount = new()
        {
            UserAccountId = userAccountId,
            Username = username,
            FirstName = "René",
            LastName = "Descartes",
            Email = "r.descartes@example.com",
            DateOfBirth = new DateTime(1596, 03, 31),
        };

        UserCredential userCredential = new()
        {
            UserCredentialId = Guid.NewGuid(),
            UserAccountId = userAccountId,
            Hash = "some-hash",
            Expiry = DateTime.MaxValue,
        };

        _authRepoMock.Setup(x => x.GetUserByUsernameAsync(username)).ReturnsAsync(userAccount);
        _authRepoMock
            .Setup(x => x.GetActiveCredentialByUserAccountIdAsync(userAccountId))
            .ReturnsAsync(userCredential);
        _passwordInfraMock
            .Setup(x => x.Verify(It.IsAny<string>(), It.IsAny<string>()))
            .Returns(true);
        _tokenServiceMock
            .Setup(x => x.GenerateAccessToken(It.IsAny<UserAccount>()))
            .Returns("access-token");
        _tokenServiceMock
            .Setup(x => x.GenerateRefreshToken(It.IsAny<UserAccount>()))
            .Returns("refresh-token");

        LoginPayload result = await _handler.Handle(
            new LoginCommand(username, "any-password"),
            CancellationToken.None
        );

        result.Should().NotBeNull();
        result.UserAccountId.Should().Be(userAccountId);
        result.Username.Should().Be(username);
        result.AccessToken.Should().Be("access-token");
        result.RefreshToken.Should().Be("refresh-token");
    }

    [Fact]
    public async Task Handle_WithUnregisteredUsername_ThrowsUnauthorizedException()
    {
        const string username = "de_beauvoir";
        _authRepoMock
            .Setup(x => x.GetUserByUsernameAsync(username))
            .ReturnsAsync((UserAccount?)null);

        Func<Task<LoginPayload>> act = async () =>
            await _handler.Handle(new LoginCommand(username, "password"), CancellationToken.None);

        await act.Should().ThrowAsync<UnauthorizedException>();
        _authRepoMock.Verify(
            x => x.GetActiveCredentialByUserAccountIdAsync(It.IsAny<Guid>()),
            Times.Never
        );
    }

    [Fact]
    public async Task Handle_WithNoActiveCredential_ThrowsUnauthorizedException()
    {
        const string username = "BRussell";
        Guid userAccountId = Guid.NewGuid();
        UserAccount userAccount = new() { UserAccountId = userAccountId, Username = username };

        _authRepoMock.Setup(x => x.GetUserByUsernameAsync(username)).ReturnsAsync(userAccount);
        _authRepoMock
            .Setup(x => x.GetActiveCredentialByUserAccountIdAsync(userAccountId))
            .ReturnsAsync((UserCredential?)null);

        Func<Task<LoginPayload>> act = async () =>
            await _handler.Handle(new LoginCommand(username, "password"), CancellationToken.None);

        await act.Should()
            .ThrowAsync<UnauthorizedException>()
            .WithMessage("Invalid username or password.");
        _passwordInfraMock.Verify(
            x => x.Verify(It.IsAny<string>(), It.IsAny<string>()),
            Times.Never
        );
    }

    [Fact]
    public async Task Handle_WithIncorrectPassword_ThrowsUnauthorizedException()
    {
        const string username = "RCarnap";
        Guid userAccountId = Guid.NewGuid();
        UserAccount userAccount = new() { UserAccountId = userAccountId, Username = username };
        UserCredential userCredential = new()
        {
            UserCredentialId = Guid.NewGuid(),
            UserAccountId = userAccountId,
            Hash = "hashed-password",
        };

        _authRepoMock.Setup(x => x.GetUserByUsernameAsync(username)).ReturnsAsync(userAccount);
        _authRepoMock
            .Setup(x => x.GetActiveCredentialByUserAccountIdAsync(userAccountId))
            .ReturnsAsync(userCredential);
        _passwordInfraMock
            .Setup(x => x.Verify(It.IsAny<string>(), It.IsAny<string>()))
            .Returns(false);

        Func<Task<LoginPayload>> act = async () =>
            await _handler.Handle(
                new LoginCommand(username, "wrong-password"),
                CancellationToken.None
            );

        await act.Should()
            .ThrowAsync<UnauthorizedException>()
            .WithMessage("Invalid username or password.");
    }
}