feat: Add unit tests and fakes for Crestron environment and data store

- Introduced `FakeCrestronEnvironment` and `FakeEthernetHelper` for testing purposes.
- Implemented `InMemoryCrestronDataStore` to facilitate unit tests for data storage.
- Created `DebugServiceTests` to validate the behavior of debug-related services.
- Added project files for unit tests targeting .NET 9.0 with necessary dependencies.
- Developed production adapters (`CrestronConsoleAdapter`, `CrestronDataStoreAdapter`, `CrestronEnvironmentAdapter`, `CrestronEthernetAdapter`) to interface with the Crestron SDK.
- Updated `Debug` class to utilize injected service abstractions instead of direct SDK calls.
- Enhanced `ControlSystem` initialization to register service adapters before usage.

src/PepperDash.Core.Tests/Logging/DebugServiceTests.cs

@@ -0,0 +1,171 @@
+using FluentAssertions;
+using PepperDash.Core.Abstractions;
+using PepperDash.Core.Tests.Fakes;
+using Xunit;
+
+namespace PepperDash.Core.Tests.Logging;
+
+/// <summary>
+/// Tests for Debug-related service interfaces and implementations.
+/// These tests verify the behaviour of the abstractions in isolation (no Crestron SDK required).
+/// </summary>
+public class DebugServiceTests
+{
+    // -----------------------------------------------------------------------
+    // ICrestronDataStore — InMemoryCrestronDataStore
+    // -----------------------------------------------------------------------
+
+    [Fact]
+    public void DataStore_InitStore_SetsInitializedFlag()
+    {
+        var store = new InMemoryCrestronDataStore();
+        store.Initialized.Should().BeFalse("not yet initialized");
+
+        store.InitStore();
+
+        store.Initialized.Should().BeTrue();
+    }
+
+    [Fact]
+    public void DataStore_SetAndGetLocalInt_RoundTrips()
+    {
+        var store = new InMemoryCrestronDataStore();
+
+        store.SetLocalInt("MyKey", 42).Should().BeTrue();
+        store.TryGetLocalInt("MyKey", out var value).Should().BeTrue();
+        value.Should().Be(42);
+    }
+
+    [Fact]
+    public void DataStore_TryGetLocalInt_ReturnsFalse_WhenKeyAbsent()
+    {
+        var store = new InMemoryCrestronDataStore();
+
+        store.TryGetLocalInt("Missing", out var value).Should().BeFalse();
+        value.Should().Be(0);
+    }
+
+    [Fact]
+    public void DataStore_SetAndGetLocalBool_RoundTrips()
+    {
+        var store = new InMemoryCrestronDataStore();
+
+        store.SetLocalBool("FlagKey", true).Should().BeTrue();
+        store.TryGetLocalBool("FlagKey", out var value).Should().BeTrue();
+        value.Should().BeTrue();
+    }
+
+    [Fact]
+    public void DataStore_TryGetLocalBool_ReturnsFalse_WhenKeyAbsent()
+    {
+        var store = new InMemoryCrestronDataStore();
+
+        store.TryGetLocalBool("Missing", out var value).Should().BeFalse();
+        value.Should().BeFalse();
+    }
+
+    [Fact]
+    public void DataStore_SetLocalUint_CanBeReadBackAsInt()
+    {
+        var store = new InMemoryCrestronDataStore();
+
+        store.SetLocalUint("UintKey", 3u).Should().BeTrue();
+        store.TryGetLocalInt("UintKey", out var value).Should().BeTrue();
+        value.Should().Be(3);
+    }
+
+    [Fact]
+    public void DataStore_Seed_AllowsTestSetupOfReadPaths()
+    {
+        var store = new InMemoryCrestronDataStore();
+        store.Seed("MyLevel", 2);
+
+        store.TryGetLocalInt("MyLevel", out var level).Should().BeTrue();
+        level.Should().Be(2);
+    }
+
+    // -----------------------------------------------------------------------
+    // DebugServiceRegistration
+    // -----------------------------------------------------------------------
+
+    [Fact]
+    public void ServiceRegistration_Register_StoresAllThreeServices()
+    {
+        var env = new FakeCrestronEnvironment();
+        var console = new NoOpCrestronConsole();
+        var store = new InMemoryCrestronDataStore();
+
+        DebugServiceRegistration.Register(env, console, store);
+
+        DebugServiceRegistration.Environment.Should().BeSameAs(env);
+        DebugServiceRegistration.Console.Should().BeSameAs(console);
+        DebugServiceRegistration.DataStore.Should().BeSameAs(store);
+    }
+
+    [Fact]
+    public void ServiceRegistration_Register_AcceptsNullsWithoutThrowing()
+    {
+        var act = () => DebugServiceRegistration.Register(null, null, null);
+        act.Should().NotThrow();
+    }
+
+    // -----------------------------------------------------------------------
+    // ICrestronEnvironment — FakeCrestronEnvironment
+    // -----------------------------------------------------------------------
+
+    [Fact]
+    public void FakeEnvironment_DefaultsToAppliance()
+    {
+        var env = new FakeCrestronEnvironment();
+        env.DevicePlatform.Should().Be(DevicePlatform.Appliance);
+    }
+
+    [Fact]
+    public void FakeEnvironment_RaiseProgramStatus_FiresEvent()
+    {
+        var env = new FakeCrestronEnvironment();
+        ProgramStatusEventType? received = null;
+        env.ProgramStatusChanged += (_, e) => received = e.EventType;
+
+        env.RaiseProgramStatus(ProgramStatusEventType.Stopping);
+
+        received.Should().Be(ProgramStatusEventType.Stopping);
+    }
+
+    [Fact]
+    public void FakeEnvironment_RaiseEthernetEvent_FiresEvent()
+    {
+        var env = new FakeCrestronEnvironment();
+        EthernetEventType? received = null;
+        env.EthernetEventReceived += (_, e) => received = e.EthernetEventType;
+
+        env.RaiseEthernetEvent(EthernetEventType.LinkUp, adapter: 0);
+
+        received.Should().Be(EthernetEventType.LinkUp);
+    }
+
+    // -----------------------------------------------------------------------
+    // ICrestronConsole — CapturingCrestronConsole
+    // -----------------------------------------------------------------------
+
+    [Fact]
+    public void CapturingConsole_PrintLine_CapturesMessage()
+    {
+        var console = new CapturingCrestronConsole();
+
+        console.PrintLine("hello world");
+
+        console.Lines.Should().ContainSingle().Which.Should().Be("hello world");
+    }
+
+    [Fact]
+    public void CapturingConsole_AddNewConsoleCommand_RecordsCommandName()
+    {
+        var console = new CapturingCrestronConsole();
+
+        console.AddNewConsoleCommand(_ => { }, "appdebug", "Sets debug level", ConsoleAccessLevel.AccessOperator);
+
+        console.RegisteredCommands.Should().ContainSingle()
+            .Which.Command.Should().Be("appdebug");
+    }
+}