fix(launcher): close LA4 review findings

tests/AcDream.Launcher.Core.Tests/Orchestration/LauncherExecutableSetTests.cs

@@ -0,0 +1,67 @@
+using AcDream.Launcher.Core.Orchestration;
+using AcDream.Launcher.Core.Profiles;
+
+namespace AcDream.Launcher.Core.Tests.Orchestration;
+
+public sealed class LauncherExecutableSetTests : IDisposable
+{
+    private readonly string _root = Path.Combine(
+        Path.GetTempPath(),
+        "acdream-launcher-layout-tests",
+        Guid.NewGuid().ToString("N"));
+
+    public void Dispose()
+    {
+        if (Directory.Exists(_root))
+        {
+            Directory.Delete(_root, recursive: true);
+        }
+    }
+
+    [Fact]
+    public void FromDirectoryResolvesThePublishedCoDeploymentLayout()
+    {
+        Directory.CreateDirectory(_root);
+        string suffix = OperatingSystem.IsWindows() ? ".exe" : string.Empty;
+        string graphical = Path.Combine(_root, "AcDream.App" + suffix);
+        string headless = Path.Combine(_root, "acdream-headless" + suffix);
+        File.WriteAllText(graphical, string.Empty);
+        File.WriteAllText(headless, string.Empty);
+
+        LauncherExecutableSet set = LauncherExecutableSet.FromDirectory(_root);
+
+        Assert.Equal(Path.GetFullPath(_root), set.WorkingDirectory);
+        Assert.Equal(graphical, set.GraphicalHostPath);
+        Assert.Equal(headless, set.HeadlessHostPath);
+        Assert.True(set.GetAvailability(LaunchMode.Gui).IsAvailable);
+        Assert.True(set.GetAvailability(LaunchMode.GuiSelect).IsAvailable);
+        Assert.True(set.GetAvailability(LaunchMode.Headless).IsAvailable);
+        Assert.Equal(
+            graphical,
+            set.CreatePlaySpec(LaunchMode.GuiSelect, "session.json").ExecutablePath);
+        Assert.Equal(
+            headless,
+            set.CreateProbeSpec("session.json").ExecutablePath);
+    }
+
+    [Fact]
+    public void MissingPublishedHostsHaveSpecificUnavailableReasons()
+    {
+        Directory.CreateDirectory(_root);
+        LauncherExecutableSet set = LauncherExecutableSet.FromDirectory(_root);
+
+        LauncherCapability gui = set.GetAvailability(LaunchMode.Gui);
+        LauncherCapability probe = set.GetAvailability(LaunchMode.Headless);
+
+        Assert.False(gui.IsAvailable);
+        Assert.Contains("graphical client", gui.Reason, StringComparison.Ordinal);
+        Assert.Contains(set.GraphicalHostPath, gui.Reason, StringComparison.Ordinal);
+        Assert.False(probe.IsAvailable);
+        Assert.Contains("headless host", probe.Reason, StringComparison.Ordinal);
+        Assert.Contains(set.HeadlessHostPath, probe.Reason, StringComparison.Ordinal);
+        Assert.Throws<LauncherOperationException>(() =>
+            set.CreatePlaySpec(LaunchMode.Gui, "session.json"));
+        Assert.Throws<LauncherOperationException>(() =>
+            set.CreateProbeSpec("session.json"));
+    }
+}