diff --git a/AcDream.slnx b/AcDream.slnx
index 760229e..5a5029d 100644
--- a/AcDream.slnx
+++ b/AcDream.slnx
@@ -15,5 +15,6 @@
     <Project Path="tests/AcDream.Core.Tests.Fixtures.HelloPlugin/AcDream.Core.Tests.Fixtures.HelloPlugin.csproj" />
     <Project Path="tests/AcDream.Core.Tests/AcDream.Core.Tests.csproj" />
     <Project Path="tests/AcDream.Core.Net.Tests/AcDream.Core.Net.Tests.csproj" />
+    <Project Path="tests/AcDream.UI.Abstractions.Tests/AcDream.UI.Abstractions.Tests.csproj" />
   </Folder>
 </Solution>
diff --git a/tests/AcDream.UI.Abstractions.Tests/AcDream.UI.Abstractions.Tests.csproj b/tests/AcDream.UI.Abstractions.Tests/AcDream.UI.Abstractions.Tests.csproj
new file mode 100644
index 0000000..f99c6e2
--- /dev/null
+++ b/tests/AcDream.UI.Abstractions.Tests/AcDream.UI.Abstractions.Tests.csproj
@@ -0,0 +1,25 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.4" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageReference Include="xunit" Version="2.9.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.4" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\AcDream.UI.Abstractions\AcDream.UI.Abstractions.csproj" />
+  </ItemGroup>
+
+</Project>
diff --git a/tests/AcDream.UI.Abstractions.Tests/NullCommandBusTests.cs b/tests/AcDream.UI.Abstractions.Tests/NullCommandBusTests.cs
new file mode 100644
index 0000000..6f34d5e
--- /dev/null
+++ b/tests/AcDream.UI.Abstractions.Tests/NullCommandBusTests.cs
@@ -0,0 +1,22 @@
+namespace AcDream.UI.Abstractions.Tests;
+
+public sealed class NullCommandBusTests
+{
+    private sealed record FakeCmd(int Value);
+
+    [Fact]
+    public void Publish_DoesNotThrow_OnAnyRecordType()
+    {
+        var bus = NullCommandBus.Instance;
+
+        bus.Publish(new FakeCmd(42));
+        bus.Publish("a string command");
+        bus.Publish(12345);
+    }
+
+    [Fact]
+    public void Instance_IsSingleton()
+    {
+        Assert.Same(NullCommandBus.Instance, NullCommandBus.Instance);
+    }
+}
diff --git a/tests/AcDream.UI.Abstractions.Tests/PanelContextTests.cs b/tests/AcDream.UI.Abstractions.Tests/PanelContextTests.cs
new file mode 100644
index 0000000..2a665c9
--- /dev/null
+++ b/tests/AcDream.UI.Abstractions.Tests/PanelContextTests.cs
@@ -0,0 +1,24 @@
+namespace AcDream.UI.Abstractions.Tests;
+
+public sealed class PanelContextTests
+{
+    [Fact]
+    public void Fields_RoundTripThroughConstructor()
+    {
+        var ctx = new PanelContext(DeltaSeconds: 0.016f, Commands: NullCommandBus.Instance);
+
+        Assert.Equal(0.016f, ctx.DeltaSeconds);
+        Assert.Same(NullCommandBus.Instance, ctx.Commands);
+    }
+
+    [Fact]
+    public void RecordEquality_ByValue()
+    {
+        var a = new PanelContext(1f / 60f, NullCommandBus.Instance);
+        var b = new PanelContext(1f / 60f, NullCommandBus.Instance);
+
+        // Record-struct equality is value-based on DeltaSeconds + reference-based
+        // on Commands (since ICommandBus is a reference type, same instance → equal).
+        Assert.Equal(a, b);
+    }
+}
diff --git a/tests/AcDream.UI.Abstractions.Tests/VitalsVMTests.cs b/tests/AcDream.UI.Abstractions.Tests/VitalsVMTests.cs
new file mode 100644
index 0000000..3abf2c3
--- /dev/null
+++ b/tests/AcDream.UI.Abstractions.Tests/VitalsVMTests.cs
@@ -0,0 +1,80 @@
+using AcDream.Core.Combat;
+using AcDream.UI.Abstractions.Panels.Vitals;
+
+namespace AcDream.UI.Abstractions.Tests;
+
+public sealed class VitalsVMTests
+{
+    [Fact]
+    public void HealthPercent_ReturnsCombatStateValue_AfterUpdateHealth()
+    {
+        var combat = new CombatState();
+        uint guid = 0x5000_0042u;
+        combat.OnUpdateHealth(guid, 0.42f);
+
+        var vm = new VitalsVM(combat);
+        vm.SetLocalPlayerGuid(guid);
+
+        Assert.Equal(0.42f, vm.HealthPercent, precision: 3);
+    }
+
+    [Fact]
+    public void HealthPercent_ReturnsOne_WhenGuidUnknown()
+    {
+        var combat = new CombatState();
+        var vm = new VitalsVM(combat);
+
+        // No SetLocalPlayerGuid call — defaults to 0 which CombatState has never seen.
+        Assert.Equal(1f, vm.HealthPercent);
+    }
+
+    [Fact]
+    public void HealthPercent_ReturnsOne_WhenGuidSetButNeverUpdated()
+    {
+        var combat = new CombatState();
+        var vm = new VitalsVM(combat);
+        vm.SetLocalPlayerGuid(0xDEAD_BEEFu);
+
+        Assert.Equal(1f, vm.HealthPercent);
+    }
+
+    [Fact]
+    public void StaminaPercent_IsNull_ForD2aScope()
+    {
+        // D.2a explicitly defers Stamina until LocalPlayerState + PlayerDescription
+        // wiring. When that arrives VitalsVM.StaminaPercent becomes non-null and
+        // VitalsPanel starts drawing the Stam bar automatically.
+        var vm = new VitalsVM(new CombatState());
+        Assert.Null(vm.StaminaPercent);
+    }
+
+    [Fact]
+    public void ManaPercent_IsNull_ForD2aScope()
+    {
+        var vm = new VitalsVM(new CombatState());
+        Assert.Null(vm.ManaPercent);
+    }
+
+    [Fact]
+    public void SetLocalPlayerGuid_ReroutesHealthLookup_WithoutStaleCache()
+    {
+        // Simulate the realistic GameWindow flow: VM is constructed pre-login
+        // with GUID=0, then SetLocalPlayerGuid is called at EnterWorld.
+        var combat = new CombatState();
+        uint playerGuid = 0x5003_E219u;
+        combat.OnUpdateHealth(playerGuid, 0.75f);
+
+        var vm = new VitalsVM(combat);
+        // Before SetLocalPlayerGuid — reads GUID=0 → returns safe 1.0.
+        Assert.Equal(1f, vm.HealthPercent);
+
+        vm.SetLocalPlayerGuid(playerGuid);
+        Assert.Equal(0.75f, vm.HealthPercent, precision: 3);
+    }
+
+    [Fact]
+    public void Constructor_ThrowsOnNullCombat()
+    {
+        Assert.Throws<ArgumentNullException>(() => new VitalsVM(null!));
+    }
+}