[gui] added host display options and per-game render settings

tests/SharpEmu.Libs.Tests/GUI/HostDisplayOptionsTests.cs

@@ -0,0 +1,51 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.GUI;
+using SharpEmu.Libs.VideoOut;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.GUI;
+
+public sealed class HostDisplayOptionsTests
+{
+    private static readonly HostDisplayInfo Display = new(
+        1,
+        "Test monitor",
+        [
+            new HostDisplayMode(2560, 1440, 144),
+            new HostDisplayMode(2560, 1440, 60),
+            new HostDisplayMode(1920, 1080, 120),
+            new HostDisplayMode(1920, 1080, 60),
+        ]);
+
+    [Fact]
+    public void BuildDisplays_PreservesUnavailableSavedIndex()
+    {
+        var displays = HostDisplayOptions.BuildDisplays([Display], 3);
+
+        Assert.Equal([1, 3], displays.Select(display => display.Index));
+        Assert.Equal(3, HostDisplayOptions.SelectDisplay(displays, 3).Index);
+    }
+
+    [Fact]
+    public void BuildResolutions_DeduplicatesModesAndPreservesCustomValue()
+    {
+        var display = new HostDisplayOption(Display);
+
+        var resolutions = HostDisplayOptions.BuildResolutions(display, "3440x1440");
+
+        Assert.Equal(["3440x1440", "2560x1440", "1920x1080"], resolutions);
+    }
+
+    [Fact]
+    public void BuildRefreshRates_FiltersResolutionAndKeepsAutomaticFirst()
+    {
+        var display = new HostDisplayOption(Display);
+
+        var rates = HostDisplayOptions.BuildRefreshRates(display, "1920x1080", 75, "Automatic");
+
+        Assert.Equal([0, 120, 75, 60], rates.Select(rate => rate.Value));
+        Assert.Equal("Automatic", rates[0].Label);
+    }
+}