TestConverter.cs

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using NetDaemon.AppModel.Common.Extensions;
using System.ComponentModel;
using System.Globalization;

namespace NetDaemon.AppModel.Tests.Config;

public class ConfigTests
{

    /// <summary>
    ///  This test is a showcase how to use custom type converters
    /// </summary>
    [Fact]
    public void TestAddYamlConfigWithTypeConverterGetsSettingsCorrectly()
    {
        // ARRANGE
        var configurationBuilder = new ConfigurationBuilder() as IConfigurationBuilder;

        configurationBuilder.AddYamlAppConfig(
            Path.Combine(AppContext.BaseDirectory,
                "Config/fixtures"));
        var configRool = configurationBuilder.Build();
        var section = configRool.GetSection("TestConfigConverter");
        // ACT
        var settings = section.Get<TestConvertedSettings>();

        // CHECK
        settings!.Entity!.EntityId
            .Should()
            .Be("light.testlight");
    }
}

#region -- Test classes --
internal class InjectMeWithConfigPlease
{
    public InjectMeWithConfigPlease(IAppConfig<TestSettings> settings)
    {
        Settings = settings;
    }

    public IAppConfig<TestSettings> Settings { get; }
}

internal class TestConvertedSettings
{
    public TestEntity? Entity { get; set; } = null;
}

[TypeConverter(typeof(TestTypeConverter))]
internal class TestEntity
{
    public TestEntity(
        string entityId
    )
    {
        EntityId = entityId;
    }

    public string EntityId { get; }
}

internal class TestTypeConverter : TypeConverter
{
    public override bool CanConvertFrom(ITypeDescriptorContext? context, Type sourceType)
    {
        return sourceType == typeof(string) || base.CanConvertFrom(context, sourceType);
    }

    public override object? ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value)
    {
        var stringValue = value as string;
        if (stringValue is not null)
            return new TestEntity(stringValue);

        return base.ConvertFrom(context, culture, value);
    }
    public override object? ConvertTo(ITypeDescriptorContext? context, CultureInfo? culture, object? value, Type destinationType)
    {
        var casted = value as TestEntity;
        if (destinationType == typeof(string) && casted is not null)
            return casted;
        return base.ConvertTo(context, culture, value, destinationType);
    }
}
#endregion