ttui/test/TinyTUI.Tests/Overlay/OverlayManagerTests.cs

using TinyTUI.Components;
using TinyTUI.Overlay;
using TinyTUI.Tests.TestInfrastructure;
using TinyTUI.Text;

namespace TinyTUI.Tests.Overlay;

public sealed class OverlayManagerTests
{
    [Fact]
    public void ComposeKeepsOverlayVisibleWhenBaseContentIsShorterThanTerminal()
    {
        var manager = new OverlayManager(new TerminalTextMeasurer());
        manager.Show(new StaticComponent(["OVERLAY_TOP", "OVERLAY_MID", "OVERLAY_BOT"]));

        var lines = manager.Compose(["Line 1", "Line 2", "Line 3"], new TerminalSize(20, 10));

        Assert.Contains(lines, line => line.Contains("OVERLAY", StringComparison.Ordinal));
    }

    [Fact]
    public void ComposePreservesBaseContentToRightOfShortOverlay()
    {
        var manager = new OverlayManager(new TerminalTextMeasurer());
        manager.Show(
            new StaticComponent(["OVR"]),
            new OverlayOptions
            {
                Row = 0,
                Column = 3,
                Width = 3,
            });

        var lines = manager.Compose(["0123456789"], new TerminalSize(10, 3));

        AnsiAssert.EqualVisible("012OVR6789", lines[0]);
    }

    [Fact]
    public void ComposeIsolatesOverlaySegmentWithResets()
    {
        var manager = new OverlayManager(new TerminalTextMeasurer());
        manager.Show(
            new StaticComponent(["OVR"]),
            new OverlayOptions
            {
                Row = 0,
                Column = 5,
                Width = 3,
            });

        var line = manager.Compose(["\e[3mXXXXXXXXXXXXXXXXXXXX\e[23m"], new TerminalSize(20, 3))[0];

        Assert.Contains("\e[0m\e]8;;\aOVR\e[0m\e]8;;\a", line, StringComparison.Ordinal);
        AnsiAssert.ContainsVisible("OVR", line);
    }

    private sealed class StaticComponent(IReadOnlyList<string> lines) : IComponent
    {
        /// <inheritdoc />
        public IReadOnlyList<string> Render(int width) => lines;

        /// <inheritdoc />
        public void Invalidate()
        {
        }
    }
}