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

LanMountainDesktop.Tests/PluginMarketCompatibilityTests.cs

@@ -0,0 +1,79 @@
+using LanMountainDesktop.Services.PluginMarket;
+using Xunit;
+
+namespace LanMountainDesktop.Tests;
+
+public sealed class PluginMarketCompatibilityTests
+{
+    [Fact]
+    public void Validate_RejectsPluginFromPreviousApiMajor()
+    {
+        var error = AirAppMarketCompatibility.Validate(
+            CreatePlugin(apiVersion: "4.0.0"),
+            new Version(0, 8, 8),
+            "5.0.0");
+
+        Assert.NotNull(error);
+        Assert.Contains("incompatible API version 4.0.0", error, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void Validate_ChecksApiMajorEvenWhenHostProductVersionIsUnavailable()
+    {
+        var error = AirAppMarketCompatibility.Validate(
+            CreatePlugin(apiVersion: "4.0.0"),
+            hostVersion: null,
+            hostApiVersion: "5.0.0");
+
+        Assert.NotNull(error);
+        Assert.Contains("Host API version is 5.0.0", error, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void Validate_RejectsPluginThatRequiresNewerHost()
+    {
+        var error = AirAppMarketCompatibility.Validate(
+            CreatePlugin(apiVersion: "5.0.0", minHostVersion: "0.9.0"),
+            new Version(0, 8, 8),
+            "5.0.0");
+
+        Assert.NotNull(error);
+        Assert.Contains("requires host version 0.9.0 or newer", error, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void Validate_AcceptsCompatiblePlugin()
+    {
+        var error = AirAppMarketCompatibility.Validate(
+            CreatePlugin(apiVersion: "5.2.0", minHostVersion: "0.8.0"),
+            new Version(0, 8, 8),
+            "5.0.0");
+
+        Assert.Null(error);
+    }
+
+    private static AirAppMarketPluginEntry CreatePlugin(
+        string apiVersion,
+        string minHostVersion = "0.0.1") =>
+        new()
+        {
+            PluginId = "Example.Plugin",
+            Id = "Example.Plugin",
+            Name = "Example Plugin",
+            Description = "Compatibility test plugin.",
+            Author = "LanMountainDesktop",
+            Version = "1.0.0",
+            ApiVersion = apiVersion,
+            MinHostVersion = minHostVersion,
+            RepositoryUrl = "https://github.com/example/example-plugin",
+            PackageSources =
+            [
+                new AirAppMarketPluginPackageSourceEntry
+                {
+                    Kind = "workspaceLocal",
+                    Url = "workspace://Example.Plugin/Example.Plugin.1.0.0.laapp",
+                    SourceKind = PluginPackageSourceKind.WorkspaceLocal
+                }
+            ]
+        };
+}