test(selftests): add FontManager ctor and push smoke steps

Two new self-test steps for the hybrid FontManager:

- FontManagerCtorSmokeStep proves all five handles land on the manager
  after Phase-1 resolve (ItalicFont nullable per Config.ItalicEnabled)
  and that no atlas-load exception is sitting on any of them
- FontPushSmokeStep proves IFontHandle.Push() returns without throwing
  for the two main delegate handles right after plugin load

Both steps run on the framework thread via the xlperf self-test path
and are registered alongside the existing theme-switch step in
SelfTestRegistry.

HellionChat/Plugin.cs

@@ -317,7 +317,11 @@ public sealed class Plugin : IAsyncDalamudPlugin
             if (_lifecycle is not null)
                 await _lifecycle.LoadAsync(cancellationToken).ConfigureAwait(false);
 
-            SelfTestRegistry.RegisterTestSteps([new SelfTests.ThemeSwitchSelfTestStep(this)]);
+            SelfTestRegistry.RegisterTestSteps([
+                new SelfTests.ThemeSwitchSelfTestStep(this),
+                new SelfTests.FontManagerCtorSmokeStep(this),
+                new SelfTests.FontPushSmokeStep(this),
+            ]);
 
             if (!Config.FirstRunCompleted)
                 FirstRunWizard.IsOpen = true;

HellionChat/SelfTests/FontManagerCtorSmokeStep.cs

@@ -0,0 +1,93 @@
+using Dalamud.Bindings.ImGui;
+using Dalamud.Plugin.SelfTest;
+
+namespace HellionChat.SelfTests;
+
+// Verifies the FontManager came out of the DI container with every
+// handle attached and no atlas-load failure on any of them. ItalicFont
+// is allowed to be null when ItalicEnabled is off.
+internal sealed class FontManagerCtorSmokeStep : ISelfTestStep
+{
+    private readonly Plugin plugin;
+
+    public FontManagerCtorSmokeStep(Plugin plugin)
+    {
+        this.plugin = plugin;
+    }
+
+    public string Name => "Hellion Chat - FontManager ctor smoke";
+
+    public SelfTestStepResult RunStep()
+    {
+        var fm = this.plugin.FontManager;
+        if (fm is null)
+        {
+            ImGui.Text("Plugin.FontManager is null");
+            return SelfTestStepResult.Fail;
+        }
+
+        if (fm.Axis is null)
+        {
+            ImGui.Text("Axis handle is null");
+            return SelfTestStepResult.Fail;
+        }
+
+        if (fm.AxisItalic is null)
+        {
+            ImGui.Text("AxisItalic handle is null");
+            return SelfTestStepResult.Fail;
+        }
+
+        if (fm.FontAwesome is null)
+        {
+            ImGui.Text("FontAwesome handle is null");
+            return SelfTestStepResult.Fail;
+        }
+
+        if (fm.RegularFont is null)
+        {
+            ImGui.Text("RegularFont handle is null");
+            return SelfTestStepResult.Fail;
+        }
+
+        if (Plugin.Config.ItalicEnabled && fm.ItalicFont is null)
+        {
+            ImGui.Text("ItalicEnabled is on but ItalicFont handle is null");
+            return SelfTestStepResult.Fail;
+        }
+
+        if (fm.Axis.LoadException is { } e1)
+        {
+            ImGui.Text($"Axis load exception: {e1.Message}");
+            return SelfTestStepResult.Fail;
+        }
+
+        if (fm.AxisItalic.LoadException is { } e2)
+        {
+            ImGui.Text($"AxisItalic load exception: {e2.Message}");
+            return SelfTestStepResult.Fail;
+        }
+
+        if (fm.FontAwesome.LoadException is { } e3)
+        {
+            ImGui.Text($"FontAwesome load exception: {e3.Message}");
+            return SelfTestStepResult.Fail;
+        }
+
+        if (fm.RegularFont.LoadException is { } e4)
+        {
+            ImGui.Text($"RegularFont load exception: {e4.Message}");
+            return SelfTestStepResult.Fail;
+        }
+
+        if (fm.ItalicFont?.LoadException is { } e5)
+        {
+            ImGui.Text($"ItalicFont load exception: {e5.Message}");
+            return SelfTestStepResult.Fail;
+        }
+
+        return SelfTestStepResult.Pass;
+    }
+
+    public void CleanUp() { }
+}

HellionChat/SelfTests/FontPushSmokeStep.cs

@@ -0,0 +1,46 @@
+using Dalamud.Bindings.ImGui;
+using Dalamud.Plugin.SelfTest;
+
+namespace HellionChat.SelfTests;
+
+// Push-safety smoke: IFontHandle.Push() is contracted safe regardless
+// of the Available state, so this step proves the ctor-built handles
+// can be pushed even right after plugin load. Self-test steps run on
+// the framework thread via the xlperf path, so the push call itself
+// stays main-thread-safe.
+internal sealed class FontPushSmokeStep : ISelfTestStep
+{
+    private readonly Plugin plugin;
+
+    public FontPushSmokeStep(Plugin plugin)
+    {
+        this.plugin = plugin;
+    }
+
+    public string Name => "Hellion Chat - FontManager push smoke";
+
+    public SelfTestStepResult RunStep()
+    {
+        var fm = this.plugin.FontManager;
+        if (fm?.RegularFont is null || fm.FontAwesome is null)
+        {
+            ImGui.Text("RegularFont or FontAwesome missing - see FontManager ctor smoke");
+            return SelfTestStepResult.Fail;
+        }
+
+        try
+        {
+            using (fm.RegularFont.Push()) { }
+            using (fm.FontAwesome.Push()) { }
+        }
+        catch (Exception e)
+        {
+            ImGui.Text($"Push threw: {e.GetType().Name}: {e.Message}");
+            return SelfTestStepResult.Fail;
+        }
+
+        return SelfTestStepResult.Pass;
+    }
+
+    public void CleanUp() { }
+}