Implement basic unit test infrastructure with abstraction patterns

Co-authored-by: ngenovese11 <23391587+ngenovese11@users.noreply.github.com>

docs/testing/QuickStart.md

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+# Quick Start Guide: Unit Testing
+
+This guide helps you get started with writing unit tests for PepperDash Essentials components.
+
+## Prerequisites
+
+- .NET 8 SDK
+- Visual Studio 2022 or VS Code with C# extension
+
+## Running Existing Tests
+
+```bash
+# Navigate to the test project
+cd tests/PepperDash.Essentials.Core.Tests
+
+# Run all tests
+dotnet test
+
+# Run with coverage
+dotnet test --collect:"XPlat Code Coverage"
+```
+
+## Creating Your First Test
+
+### 1. Identify the Component
+
+Choose a component that has business logic you want to test. Look for classes that:
+- Have clear inputs and outputs
+- Contain conditional logic or algorithms
+- Are used by multiple parts of the system
+
+### 2. Create Test File
+
+Create a new test file in `tests/PepperDash.Essentials.Core.Tests/Unit/`:
+
+```csharp
+using PepperDash.Essentials.Core.Tests.Abstractions;
+
+namespace PepperDash.Essentials.Core.Tests.Unit
+{
+    public class YourComponentTests
+    {
+        [Fact]
+        public void YourMethod_WithValidInput_ReturnsExpectedResult()
+        {
+            // Arrange
+            var component = new YourComponent();
+            var input = "test data";
+
+            // Act
+            var result = component.YourMethod(input);
+
+            // Assert
+            Assert.Equal("expected result", result);
+        }
+    }
+}
+```
+
+### 3. Abstract Dependencies
+
+If your component uses Crestron SDK or other external dependencies:
+
+```csharp
+// Create interface in Abstractions/
+public interface IYourDependency
+{
+    string DoSomething(string input);
+}
+
+// Modify your component to use the interface
+public class YourComponent
+{
+    private readonly IYourDependency _dependency;
+    
+    public YourComponent(IYourDependency dependency)
+    {
+        _dependency = dependency;
+    }
+    
+    public string YourMethod(string input)
+    {
+        return _dependency.DoSomething(input);
+    }
+}
+
+// Test with mocks
+[Fact]
+public void YourMethod_CallsDependency_ReturnsResult()
+{
+    // Arrange
+    var mockDependency = new Mock<IYourDependency>();
+    mockDependency.Setup(x => x.DoSomething("input")).Returns("output");
+    var component = new YourComponent(mockDependency.Object);
+
+    // Act
+    var result = component.YourMethod("input");
+
+    // Assert
+    Assert.Equal("output", result);
+    mockDependency.Verify(x => x.DoSomething("input"), Times.Once);
+}
+```
+
+## Testing Patterns
+
+### Testing Exceptions
+
+```csharp
+[Fact]
+public void Constructor_WithNullDependency_ThrowsArgumentNullException()
+{
+    // Act & Assert
+    Assert.Throws<ArgumentNullException>(() => new YourComponent(null));
+}
+```
+
+### Testing Async Methods
+
+```csharp
+[Fact]
+public async Task YourAsyncMethod_WithValidInput_ReturnsExpectedResult()
+{
+    // Arrange
+    var component = new YourComponent();
+
+    // Act
+    var result = await component.YourAsyncMethod();
+
+    // Assert
+    Assert.True(result);
+}
+```
+
+### Testing Collections
+
+```csharp
+[Fact]
+public void GetItems_ReturnsExpectedCount()
+{
+    // Arrange
+    var component = new YourComponent();
+
+    // Act
+    var items = component.GetItems();
+
+    // Assert
+    Assert.Equal(3, items.Count());
+    Assert.Contains(items, x => x.Name == "Expected Item");
+}
+```
+
+## Common Mistakes to Avoid
+
+1. **Testing Implementation Details** - Test behavior, not internal implementation
+2. **Overly Complex Tests** - Keep tests simple and focused on one thing
+3. **Not Testing Edge Cases** - Include null values, empty collections, boundary conditions
+4. **Ignoring Test Performance** - Tests should run quickly to enable fast feedback
+
+## Debugging Tests
+
+### In Visual Studio
+- Set breakpoints in test methods
+- Use Test Explorer to run individual tests
+- Check test output window for detailed information
+
+### From Command Line
+```bash
+# Run specific test
+dotnet test --filter "YourComponentTests.YourMethod_WithValidInput_ReturnsExpectedResult"
+
+# Run with detailed output
+dotnet test --verbosity diagnostic
+```
+
+## Next Steps
+
+1. **Review Examples** - Look at `TestableActionSequenceTests.cs` for comprehensive examples
+2. **Start Small** - Begin with simple components and build up complexity
+3. **Read Documentation** - Check `docs/testing/README.md` for detailed patterns
+4. **Get Feedback** - Have your tests reviewed by team members
+
+## Need Help?
+
+- Check existing test examples in the codebase
+- Review the full testing documentation
+- Ask team members for guidance on complex scenarios
+- Consider pair programming for your first few tests