acdream/tests/AcDream.App.Tests/Input/OutboundInteractionQueueTests.cs

using AcDream.App.Input;

namespace AcDream.App.Tests.Input;

public sealed class OutboundInteractionQueueTests
{
    [Fact]
    public void Drain_PreservesInputOrder()
    {
        var queue = new OutboundInteractionQueue();
        var actual = new List<string>();

        queue.Enqueue(() => actual.Add("use-corpse"));
        queue.Enqueue(() => actual.Add("pickup-item"));

        queue.Drain();

        Assert.Equal(new[] { "use-corpse", "pickup-item" }, actual);
        Assert.Equal(0, queue.Count);
    }

    [Fact]
    public void Drain_ReentrantEnqueueWaitsForNextFrame()
    {
        var queue = new OutboundInteractionQueue();
        var actual = new List<string>();
        queue.Enqueue(() =>
        {
            actual.Add("first");
            queue.Enqueue(() => actual.Add("next-frame"));
        });

        queue.Drain();

        Assert.Equal(new[] { "first" }, actual);
        Assert.Equal(1, queue.Count);

        queue.Drain();

        Assert.Equal(new[] { "first", "next-frame" }, actual);
        Assert.Equal(0, queue.Count);
    }

    [Fact]
    public void Clear_DropsPendingSessionActions()
    {
        var queue = new OutboundInteractionQueue();
        bool invoked = false;
        queue.Enqueue(() => invoked = true);

        queue.Clear();
        queue.Drain();

        Assert.False(invoked);
    }

    [Fact]
    public void Drain_ReentrantClearStopsTheCapturedBatch()
    {
        var queue = new OutboundInteractionQueue();
        var actual = new List<string>();
        queue.Enqueue(() =>
        {
            actual.Add("first");
            queue.Clear();
        });
        queue.Enqueue(() => actual.Add("stale"));

        queue.Drain();

        Assert.Equal(new[] { "first" }, actual);
        Assert.Equal(0, queue.Count);
    }

    [Fact]
    public void Drain_ReentrantClearAndEnqueueDefersTheNewEpoch()
    {
        var queue = new OutboundInteractionQueue();
        var actual = new List<string>();
        queue.Enqueue(() =>
        {
            actual.Add("first");
            queue.Clear();
            queue.Enqueue(() => actual.Add("new-session"));
        });
        queue.Enqueue(() => actual.Add("stale"));

        queue.Drain();
        Assert.Equal(new[] { "first" }, actual);
        Assert.Equal(1, queue.Count);

        queue.Drain();
        Assert.Equal(new[] { "first", "new-session" }, actual);
    }
}