feat: implement plugin market installation service and associated infrastructure for desktop widgets and window management

LanMountainDesktop.Tests/FusedDesktopScreenTopologyTests.cs

@@ -0,0 +1,57 @@
+using Avalonia;
+using LanMountainDesktop.Services;
+using Xunit;
+
+namespace LanMountainDesktop.Tests;
+
+public sealed class FusedDesktopScreenTopologyTests
+{
+    [Fact]
+    public void RemovedMonitorPositionMovesToNearestRemainingWorkingArea()
+    {
+        var screens = new[]
+        {
+            new FusedDesktopScreenWorkArea(new PixelRect(0, 0, 1920, 1040), 1d)
+        };
+
+        var result = FusedDesktopManagerService.CoerceToValidWorkingArea(
+            new PixelPoint(-2600, 200),
+            new Size(300, 180),
+            screens);
+
+        Assert.Equal(new PixelPoint(0, 200), result);
+    }
+
+    [Fact]
+    public void HighDpiWorkingAreaKeepsEntireWidgetVisible()
+    {
+        var screens = new[]
+        {
+            new FusedDesktopScreenWorkArea(new PixelRect(0, 0, 1920, 1040), 2d)
+        };
+
+        var result = FusedDesktopManagerService.CoerceToValidWorkingArea(
+            new PixelPoint(1800, 980),
+            new Size(200, 120),
+            screens);
+
+        Assert.Equal(new PixelPoint(1520, 800), result);
+    }
+
+    [Fact]
+    public void NegativeCoordinateMonitorUsesItsOwnWorkAreaAndScaling()
+    {
+        var screens = new[]
+        {
+            new FusedDesktopScreenWorkArea(new PixelRect(-1920, 0, 1920, 1080), 1d),
+            new FusedDesktopScreenWorkArea(new PixelRect(0, 0, 2560, 1400), 1.5d)
+        };
+
+        var result = FusedDesktopManagerService.CoerceToValidWorkingArea(
+            new PixelPoint(-100, 1000),
+            new Size(200, 200),
+            screens);
+
+        Assert.Equal(new PixelPoint(-200, 880), result);
+    }
+}