jdescopingtool/NEW/tests/JdeScoping.ConfigManager.Tests/Services/ConfigFileServiceTests.cs

using JdeScoping.ConfigManager.Models;
using JdeScoping.ConfigManager.Services;

namespace JdeScoping.ConfigManager.Tests.Services;

public class ConfigFileServiceTests
{
    private readonly IFileSystem _fileSystem;
    private readonly ConfigFileService _sut;

    public ConfigFileServiceTests()
    {
        _fileSystem = Substitute.For<IFileSystem>();
        _sut = new ConfigFileService(_fileSystem);
    }

    [Fact]
    public async Task LoadAppSettingsAsync_WithValidJson_ReturnsConfigModel()
    {
        // Arrange
        var json = """
        {
            "DataSync": {
                "Enabled": true,
                "MaxDegreeOfParallelism": 8
            }
        }
        """;
        _fileSystem.ReadAllTextAsync(Arg.Any<string>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult(json));

        // Act
        var result = await _sut.LoadAppSettingsAsync("/config/appsettings.json");

        // Assert
        result.ShouldNotBeNull();
        result.DataSync.Enabled.ShouldBeTrue();
        result.DataSync.MaxDegreeOfParallelism.ShouldBe(8);
    }

    [Fact]
    public async Task LoadAppSettingsAsync_WithInvalidJson_ThrowsWithHelpfulMessage()
    {
        // Arrange
        var json = "{ invalid json }";
        _fileSystem.ReadAllTextAsync(Arg.Any<string>(), Arg.Any<CancellationToken>())
            .Returns(Task.FromResult(json));

        // Act & Assert
        var ex = await Should.ThrowAsync<ConfigLoadException>(
            () => _sut.LoadAppSettingsAsync("/config/appsettings.json"));
        ex.Message.ShouldContain("parse");
    }
}