ListingSourceCodeServiceTests.cs

using EssentialCSharp.Web.Models;
using EssentialCSharp.Web.Services;

namespace EssentialCSharp.Web.Tests;

public class ListingSourceCodeServiceTests
{
    [Test]
    public async Task GetListingAsync_WithValidChapterAndListing_ReturnsCorrectListing()
    {
        // Arrange
        ListingSourceCodeService service = CreateService();

        // Act
        ListingSourceCodeResponse? result = await service.GetListingAsync(1, 1);

        // Assert
        await Assert.That(result).IsNotNull();
        using (Assert.Multiple())
        {
            await Assert.That(result.ChapterNumber).IsEqualTo(1);
            await Assert.That(result.ListingNumber).IsEqualTo(1);
            await Assert.That(result.FileExtension).IsEqualTo("cs");
            await Assert.That(result.Content).IsNotEmpty();
        }
    }

    [Test]
    public async Task GetListingAsync_WithInvalidChapter_ReturnsNull()
    {
        // Arrange
        ListingSourceCodeService service = CreateService();

        // Act
        ListingSourceCodeResponse? result = await service.GetListingAsync(999, 1);

        // Assert
        await Assert.That(result).IsNull();
    }

    [Test]
    public async Task GetListingAsync_WithInvalidListing_ReturnsNull()
    {
        // Arrange
        ListingSourceCodeService service = CreateService();

        // Act
        ListingSourceCodeResponse? result = await service.GetListingAsync(1, 999);

        // Assert
        await Assert.That(result).IsNull();
    }

    [Test]
    public async Task GetListingAsync_DifferentFileExtension_AutoDiscoversFileExtension()
    {
        // Arrange
        ListingSourceCodeService service = CreateService();

        // Act - Get an XML file (01.02.xml exists in Chapter 1)
        ListingSourceCodeResponse? result = await service.GetListingAsync(1, 2);

        // Assert
        await Assert.That(result).IsNotNull();
        await Assert.That(result.FileExtension).IsEqualTo("xml");
    }

    [Test]
    public async Task GetListingsByChapterAsync_WithValidChapter_ReturnsAllListings()
    {
        // Arrange
        ListingSourceCodeService service = CreateService();

        // Act
        IReadOnlyList<ListingSourceCodeResponse> results = await service.GetListingsByChapterAsync(1);

        // Assert
        await Assert.That(results).IsNotEmpty();
        foreach (var r in results)
        {
            using (Assert.Multiple())
            {
                await Assert.That(r.ChapterNumber).IsEqualTo(1);
                await Assert.That(r.Content).IsNotEmpty();
                await Assert.That(r.FileExtension).IsNotEmpty();
            }
        }

        // Verify results are ordered
        await Assert.That(results).IsOrderedBy(r => r.ListingNumber);
    }

    [Test]
    public async Task GetListingsByChapterAsync_DirectoryContainsNonListingFiles_ExcludesNonListingFiles()
    {
        // Arrange - Chapter 10 has Employee.cs which doesn't match the pattern
        ListingSourceCodeService service = CreateService();

        // Act
        IReadOnlyList<ListingSourceCodeResponse> results = await service.GetListingsByChapterAsync(10);

        // Assert
        await Assert.That(results).IsNotEmpty();

        // Ensure all results match the {CC}.{LL}.{ext} pattern
        foreach (var r in results)
        {
            using (Assert.Multiple())
            {
                await Assert.That(r.ChapterNumber).IsEqualTo(10);
                await Assert.That(r.ListingNumber).IsBetween(1, 99);
            }
        }
    }

    [Test]
    public async Task GetListingsByChapterAsync_WithInvalidChapter_ReturnsEmptyList()
    {
        // Arrange
        ListingSourceCodeService service = CreateService();

        // Act
        IReadOnlyList<ListingSourceCodeResponse> results = await service.GetListingsByChapterAsync(999);

        // Assert
        await Assert.That(results).IsEmpty();
    }

    private static ListingSourceCodeService CreateService() =>
        TestListingSourceCodeServiceHelper.CreateService();
}