Implement InMemory Transport Layer for StellaOps Router

- Added InMemoryTransportOptions class for configuration settings including timeouts and latency.
- Developed InMemoryTransportServer class to handle connections, frame processing, and event management.
- Created ServiceCollectionExtensions for easy registration of InMemory transport services.
- Established project structure and dependencies for InMemory transport library.
- Implemented comprehensive unit tests for endpoint discovery, connection management, request/response flow, and streaming capabilities.
- Ensured proper handling of cancellation, heartbeat, and hello frames within the transport layer.

tests/StellaOps.Microservice.Tests/EndpointDiscoveryTests.cs

@@ -0,0 +1,128 @@
+using System.Reflection;
+using StellaOps.Microservice;
+using Xunit;
+
+namespace StellaOps.Microservice.Tests;
+
+// Test endpoint classes
+[StellaEndpoint("GET", "/api/test")]
+public class TestGetEndpoint : IStellaEndpoint<string>
+{
+    public Task<string> HandleAsync(CancellationToken cancellationToken) => Task.FromResult("OK");
+}
+
+[StellaEndpoint("POST", "/api/create", SupportsStreaming = true, TimeoutSeconds = 60)]
+public class TestPostEndpoint : IStellaEndpoint<TestRequest, TestResponse>
+{
+    public Task<TestResponse> HandleAsync(TestRequest request, CancellationToken cancellationToken)
+        => Task.FromResult(new TestResponse());
+}
+
+public record TestRequest;
+public record TestResponse;
+
+public class EndpointDiscoveryTests
+{
+    [Fact]
+    public void StellaEndpointAttribute_StoresMethodAndPath()
+    {
+        // Arrange & Act
+        var attr = new StellaEndpointAttribute("POST", "/api/test");
+
+        // Assert
+        Assert.Equal("POST", attr.Method);
+        Assert.Equal("/api/test", attr.Path);
+    }
+
+    [Fact]
+    public void StellaEndpointAttribute_NormalizesMethod()
+    {
+        // Arrange & Act
+        var attr = new StellaEndpointAttribute("get", "/api/test");
+
+        // Assert
+        Assert.Equal("GET", attr.Method);
+    }
+
+    [Fact]
+    public void StellaEndpointAttribute_DefaultTimeoutIs30Seconds()
+    {
+        // Arrange & Act
+        var attr = new StellaEndpointAttribute("GET", "/api/test");
+
+        // Assert
+        Assert.Equal(30, attr.TimeoutSeconds);
+    }
+
+    [Fact]
+    public void ReflectionDiscovery_FindsEndpointsInCurrentAssembly()
+    {
+        // Arrange
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "test-service",
+            Version = "1.0.0",
+            Region = "eu1"
+        };
+        var discovery = new ReflectionEndpointDiscoveryProvider(
+            options,
+            [Assembly.GetExecutingAssembly()]);
+
+        // Act
+        var endpoints = discovery.DiscoverEndpoints();
+
+        // Assert
+        Assert.True(endpoints.Count >= 2);
+        Assert.Contains(endpoints, e => e.Method == "GET" && e.Path == "/api/test");
+        Assert.Contains(endpoints, e => e.Method == "POST" && e.Path == "/api/create");
+    }
+
+    [Fact]
+    public void ReflectionDiscovery_SetsServiceNameAndVersion()
+    {
+        // Arrange
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "my-service",
+            Version = "2.0.0",
+            Region = "eu1"
+        };
+        var discovery = new ReflectionEndpointDiscoveryProvider(
+            options,
+            [Assembly.GetExecutingAssembly()]);
+
+        // Act
+        var endpoints = discovery.DiscoverEndpoints();
+        var endpoint = endpoints.First(e => e.Path == "/api/test");
+
+        // Assert
+        Assert.Equal("my-service", endpoint.ServiceName);
+        Assert.Equal("2.0.0", endpoint.Version);
+    }
+
+    [Fact]
+    public void ReflectionDiscovery_SetsStreamingAndTimeout()
+    {
+        // Arrange
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "test",
+            Version = "1.0.0",
+            Region = "eu1"
+        };
+        var discovery = new ReflectionEndpointDiscoveryProvider(
+            options,
+            [Assembly.GetExecutingAssembly()]);
+
+        // Act
+        var endpoints = discovery.DiscoverEndpoints();
+        var postEndpoint = endpoints.First(e => e.Path == "/api/create");
+        var getEndpoint = endpoints.First(e => e.Path == "/api/test");
+
+        // Assert
+        Assert.True(postEndpoint.SupportsStreaming);
+        Assert.Equal(TimeSpan.FromSeconds(60), postEndpoint.DefaultTimeout);
+        Assert.False(getEndpoint.SupportsStreaming);
+        Assert.Equal(TimeSpan.FromSeconds(30), getEndpoint.DefaultTimeout);
+    }
+}

tests/StellaOps.Microservice.Tests/StellaMicroserviceOptionsTests.cs

@@ -1,5 +1,5 @@
 using StellaOps.Microservice;
-using StellaOps.Router.Common;
+using StellaOps.Router.Common.Enums;
 using Xunit;
 
 namespace StellaOps.Microservice.Tests;
@@ -40,4 +40,98 @@ public class StellaMicroserviceOptionsTests
         Assert.Equal(5000, config.Port);
         Assert.Equal(TransportType.Tcp, config.TransportType);
     }
+
+    [Fact]
+    public void Validate_ThrowsIfServiceNameEmpty()
+    {
+        // Arrange
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "",
+            Version = "1.0.0",
+            Region = "eu1"
+        };
+
+        // Act & Assert
+        Assert.Throws<InvalidOperationException>(() => options.Validate());
+    }
+
+    [Fact]
+    public void Validate_ThrowsIfVersionInvalid()
+    {
+        // Arrange
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "test",
+            Version = "not-semver",
+            Region = "eu1"
+        };
+
+        // Act & Assert
+        var ex = Assert.Throws<InvalidOperationException>(() => options.Validate());
+        Assert.Contains("not valid semver", ex.Message);
+    }
+
+    [Fact]
+    public void Validate_ThrowsIfNoRouters()
+    {
+        // Arrange
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "test",
+            Version = "1.0.0",
+            Region = "eu1"
+        };
+
+        // Act & Assert
+        var ex = Assert.Throws<InvalidOperationException>(() => options.Validate());
+        Assert.Contains("router endpoint is required", ex.Message);
+    }
+
+    [Fact]
+    public void Validate_AcceptsValidSemver()
+    {
+        // Arrange
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "test",
+            Version = "1.0.0",
+            Region = "eu1",
+            Routers = [new RouterEndpointConfig { Host = "localhost", Port = 5000 }]
+        };
+
+        // Act & Assert - no exception
+        options.Validate();
+    }
+
+    [Fact]
+    public void Validate_AcceptsSemverWithPrerelease()
+    {
+        // Arrange
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "test",
+            Version = "2.1.0-beta.1",
+            Region = "eu1",
+            Routers = [new RouterEndpointConfig { Host = "localhost", Port = 5000 }]
+        };
+
+        // Act & Assert - no exception
+        options.Validate();
+    }
+
+    [Fact]
+    public void DefaultHeartbeatInterval_Is10Seconds()
+    {
+        // Arrange & Act
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "test",
+            Version = "1.0.0",
+            Region = "eu1"
+        };
+
+        // Assert
+        Assert.Equal(TimeSpan.FromSeconds(10), options.HeartbeatInterval);
+    }
 }