Add unit tests for RabbitMq and Udp transport servers and clients

- Implemented comprehensive unit tests for RabbitMqTransportServer, covering constructor, disposal, connection management, event handlers, and exception handling.
- Added configuration tests for RabbitMqTransportServer to validate SSL, durable queues, auto-recovery, and custom virtual host options.
- Created unit tests for UdpFrameProtocol, including frame parsing and serialization, header size validation, and round-trip data preservation.
- Developed tests for UdpTransportClient, focusing on connection handling, event subscriptions, and exception scenarios.
- Established tests for UdpTransportServer, ensuring proper start/stop behavior, connection state management, and event handling.
- Included tests for UdpTransportOptions to verify default values and modification capabilities.
- Enhanced service registration tests for Udp transport services in the dependency injection container.

src/__Libraries/__Tests/StellaOps.Microservice.Tests/EndpointDiscoveryServiceTests.cs

@@ -0,0 +1,197 @@
+using Microsoft.Extensions.Logging.Abstractions;
+using Moq;
+using StellaOps.Router.Common.Models;
+
+namespace StellaOps.Microservice.Tests;
+
+/// <summary>
+/// Unit tests for <see cref="EndpointDiscoveryService"/>.
+/// </summary>
+public sealed class EndpointDiscoveryServiceTests
+{
+    private readonly Mock<IEndpointDiscoveryProvider> _discoveryProviderMock;
+    private readonly Mock<IMicroserviceYamlLoader> _yamlLoaderMock;
+    private readonly Mock<IEndpointOverrideMerger> _mergerMock;
+
+    public EndpointDiscoveryServiceTests()
+    {
+        _discoveryProviderMock = new Mock<IEndpointDiscoveryProvider>();
+        _yamlLoaderMock = new Mock<IMicroserviceYamlLoader>();
+        _mergerMock = new Mock<IEndpointOverrideMerger>();
+
+        // Default setups
+        _discoveryProviderMock.Setup(d => d.DiscoverEndpoints())
+            .Returns(new List<EndpointDescriptor>());
+        _yamlLoaderMock.Setup(l => l.Load())
+            .Returns((MicroserviceYamlConfig?)null);
+        _mergerMock.Setup(m => m.Merge(It.IsAny<IReadOnlyList<EndpointDescriptor>>(), It.IsAny<MicroserviceYamlConfig?>()))
+            .Returns<IReadOnlyList<EndpointDescriptor>, MicroserviceYamlConfig?>((e, _) => e);
+    }
+
+    private EndpointDiscoveryService CreateService()
+    {
+        return new EndpointDiscoveryService(
+            _discoveryProviderMock.Object,
+            _yamlLoaderMock.Object,
+            _mergerMock.Object,
+            NullLogger<EndpointDiscoveryService>.Instance);
+    }
+
+    #region DiscoverEndpoints Tests
+
+    [Fact]
+    public void DiscoverEndpoints_CallsDiscoveryProvider()
+    {
+        // Arrange
+        var service = CreateService();
+
+        // Act
+        service.DiscoverEndpoints();
+
+        // Assert
+        _discoveryProviderMock.Verify(d => d.DiscoverEndpoints(), Times.Once);
+    }
+
+    [Fact]
+    public void DiscoverEndpoints_LoadsYamlConfig()
+    {
+        // Arrange
+        var service = CreateService();
+
+        // Act
+        service.DiscoverEndpoints();
+
+        // Assert
+        _yamlLoaderMock.Verify(l => l.Load(), Times.Once);
+    }
+
+    [Fact]
+    public void DiscoverEndpoints_MergesCodeAndYaml()
+    {
+        // Arrange
+        var codeEndpoints = new List<EndpointDescriptor>
+        {
+            new() { ServiceName = "test", Version = "1.0", Method = "GET", Path = "/api/users" }
+        };
+        _discoveryProviderMock.Setup(d => d.DiscoverEndpoints()).Returns(codeEndpoints);
+
+        var yamlConfig = new MicroserviceYamlConfig
+        {
+            Endpoints =
+            [
+                new EndpointOverrideConfig { Method = "GET", Path = "/api/users", DefaultTimeout = "30s" }
+            ]
+        };
+        _yamlLoaderMock.Setup(l => l.Load()).Returns(yamlConfig);
+
+        var service = CreateService();
+
+        // Act
+        service.DiscoverEndpoints();
+
+        // Assert
+        _mergerMock.Verify(m => m.Merge(codeEndpoints, yamlConfig), Times.Once);
+    }
+
+    [Fact]
+    public void DiscoverEndpoints_ReturnsMergedEndpoints()
+    {
+        // Arrange
+        var codeEndpoints = new List<EndpointDescriptor>
+        {
+            new() { ServiceName = "test", Version = "1.0", Method = "GET", Path = "/api/users" }
+        };
+        _discoveryProviderMock.Setup(d => d.DiscoverEndpoints()).Returns(codeEndpoints);
+
+        var mergedEndpoints = new List<EndpointDescriptor>
+        {
+            new() { ServiceName = "test", Version = "1.0", Method = "GET", Path = "/api/users", DefaultTimeout = TimeSpan.FromSeconds(30) }
+        };
+        _mergerMock.Setup(m => m.Merge(It.IsAny<IReadOnlyList<EndpointDescriptor>>(), It.IsAny<MicroserviceYamlConfig?>()))
+            .Returns(mergedEndpoints);
+
+        var service = CreateService();
+
+        // Act
+        var result = service.DiscoverEndpoints();
+
+        // Assert
+        result.Should().BeSameAs(mergedEndpoints);
+    }
+
+    [Fact]
+    public void DiscoverEndpoints_WhenYamlLoadFails_UsesCodeEndpointsOnly()
+    {
+        // Arrange
+        var codeEndpoints = new List<EndpointDescriptor>
+        {
+            new() { ServiceName = "test", Version = "1.0", Method = "GET", Path = "/api/users" }
+        };
+        _discoveryProviderMock.Setup(d => d.DiscoverEndpoints()).Returns(codeEndpoints);
+        _yamlLoaderMock.Setup(l => l.Load()).Throws(new FileNotFoundException("YAML not found"));
+
+        var service = CreateService();
+
+        // Act
+        service.DiscoverEndpoints();
+
+        // Assert - merger should be called with null config
+        _mergerMock.Verify(m => m.Merge(codeEndpoints, null), Times.Once);
+    }
+
+    [Fact]
+    public void DiscoverEndpoints_WithMultipleEndpoints_ReturnsAll()
+    {
+        // Arrange
+        var endpoints = new List<EndpointDescriptor>
+        {
+            new() { ServiceName = "test", Version = "1.0", Method = "GET", Path = "/api/users" },
+            new() { ServiceName = "test", Version = "1.0", Method = "POST", Path = "/api/users" },
+            new() { ServiceName = "test", Version = "1.0", Method = "GET", Path = "/api/users/{id}" },
+            new() { ServiceName = "test", Version = "1.0", Method = "DELETE", Path = "/api/users/{id}" }
+        };
+        _discoveryProviderMock.Setup(d => d.DiscoverEndpoints()).Returns(endpoints);
+        _mergerMock.Setup(m => m.Merge(endpoints, null)).Returns(endpoints);
+
+        var service = CreateService();
+
+        // Act
+        var result = service.DiscoverEndpoints();
+
+        // Assert
+        result.Should().HaveCount(4);
+    }
+
+    [Fact]
+    public void DiscoverEndpoints_EmptyEndpoints_ReturnsEmptyList()
+    {
+        // Arrange
+        _discoveryProviderMock.Setup(d => d.DiscoverEndpoints()).Returns(new List<EndpointDescriptor>());
+        _mergerMock.Setup(m => m.Merge(It.IsAny<IReadOnlyList<EndpointDescriptor>>(), null))
+            .Returns(new List<EndpointDescriptor>());
+
+        var service = CreateService();
+
+        // Act
+        var result = service.DiscoverEndpoints();
+
+        // Assert
+        result.Should().BeEmpty();
+    }
+
+    [Fact]
+    public void DiscoverEndpoints_CanBeCalledMultipleTimes()
+    {
+        // Arrange
+        var service = CreateService();
+
+        // Act
+        var result1 = service.DiscoverEndpoints();
+        var result2 = service.DiscoverEndpoints();
+
+        // Assert
+        _discoveryProviderMock.Verify(d => d.DiscoverEndpoints(), Times.Exactly(2));
+    }
+
+    #endregion
+}