lmxopcua/tests/ZB.MOM.WW.LmxOpcUa.Tests/Historian/HistorianPluginLoaderTests.cs

using Shouldly;
using Xunit;
using ZB.MOM.WW.LmxOpcUa.Host.Configuration;
using ZB.MOM.WW.LmxOpcUa.Host.Historian;

namespace ZB.MOM.WW.LmxOpcUa.Tests.Historian
{
    /// <summary>
    ///     Verifies the load-outcome state machine of <see cref="HistorianPluginLoader"/>.
    /// </summary>
    public class HistorianPluginLoaderTests
    {
        /// <summary>
        ///     MarkDisabled publishes a Disabled outcome so the dashboard can distinguish
        ///     "feature off" from "load failed."
        /// </summary>
        [Fact]
        public void MarkDisabled_PublishesDisabledOutcome()
        {
            HistorianPluginLoader.MarkDisabled();

            HistorianPluginLoader.LastOutcome.Status.ShouldBe(HistorianPluginStatus.Disabled);
            HistorianPluginLoader.LastOutcome.Error.ShouldBeNull();
        }

        /// <summary>
        ///     When the plugin directory is missing, TryLoad reports NotFound — not LoadFailed —
        ///     and returns null so the server can start with history disabled.
        /// </summary>
        [Fact]
        public void TryLoad_PluginMissing_ReturnsNullWithNotFoundOutcome()
        {
            // The test process runs from a bin directory that does not contain a Historian/
            // subfolder, so TryLoad will take the file-missing branch.
            var config = new HistorianConfiguration { Enabled = true };

            var result = HistorianPluginLoader.TryLoad(config);

            result.ShouldBeNull();
            HistorianPluginLoader.LastOutcome.Status.ShouldBe(HistorianPluginStatus.NotFound);
            HistorianPluginLoader.LastOutcome.PluginPath.ShouldContain("ZB.MOM.WW.LmxOpcUa.Historian.Aveva.dll");
            HistorianPluginLoader.LastOutcome.Error.ShouldBeNull();
        }
    }
}