Add unit tests for Router configuration and transport layers

- Implemented tests for RouterConfig, RoutingOptions, StaticInstanceConfig, and RouterConfigOptions to ensure default values are set correctly.
- Added tests for RouterConfigProvider to validate configurations and ensure defaults are returned when no file is specified.
- Created tests for ConfigValidationResult to check success and error scenarios.
- Developed tests for ServiceCollectionExtensions to verify service registration for RouterConfig.
- Introduced UdpTransportTests to validate serialization, connection, request-response, and error handling in UDP transport.
- Added scripts for signing authority gaps and hashing DevPortal SDK snippets.

examples/router/tests/Examples.Integration.Tests/MultiServiceRoutingTests.cs

@@ -0,0 +1,79 @@
+using System.Net;
+using FluentAssertions;
+using Xunit;
+
+namespace Examples.Integration.Tests;
+
+/// <summary>
+/// Tests that verify multiple microservices can register and receive
+/// correctly routed requests through the gateway.
+/// </summary>
+public sealed class MultiServiceRoutingTests : IClassFixture<GatewayFixture>
+{
+    private readonly GatewayFixture _fixture;
+
+    public MultiServiceRoutingTests(GatewayFixture fixture)
+    {
+        _fixture = fixture;
+    }
+
+    [Fact]
+    public async Task Gateway_RoutesBillingRequests_ToBillingService()
+    {
+        // Act
+        var response = await _fixture.GatewayClient.GetAsync("/invoices/INV-001");
+
+        // Assert
+        response.StatusCode.Should().Be(HttpStatusCode.OK);
+        var content = await response.Content.ReadAsStringAsync();
+        content.Should().Contain("INV-001");
+    }
+
+    [Fact]
+    public async Task Gateway_RoutesInventoryRequests_ToInventoryService()
+    {
+        // Act
+        var response = await _fixture.GatewayClient.GetAsync("/items/SKU-001");
+
+        // Assert
+        response.StatusCode.Should().Be(HttpStatusCode.OK);
+        var content = await response.Content.ReadAsStringAsync();
+        content.Should().Contain("SKU-001");
+    }
+
+    [Fact]
+    public async Task Gateway_HandlesSequentialRequestsToDifferentServices()
+    {
+        // Act - Send requests to both services
+        var billingResponse = await _fixture.GatewayClient.GetAsync("/invoices/INV-001");
+        var inventoryResponse = await _fixture.GatewayClient.GetAsync("/items/SKU-001");
+
+        // Assert - Both should succeed
+        billingResponse.StatusCode.Should().Be(HttpStatusCode.OK);
+        inventoryResponse.StatusCode.Should().Be(HttpStatusCode.OK);
+    }
+
+    [Fact]
+    public async Task Gateway_HandlesConcurrentRequestsToDifferentServices()
+    {
+        // Act - Send requests to both services concurrently
+        var billingTask = _fixture.GatewayClient.GetAsync("/invoices/INV-001");
+        var inventoryTask = _fixture.GatewayClient.GetAsync("/items/SKU-001");
+
+        await Task.WhenAll(billingTask, inventoryTask);
+
+        // Assert - Both should succeed
+        billingTask.Result.StatusCode.Should().Be(HttpStatusCode.OK);
+        inventoryTask.Result.StatusCode.Should().Be(HttpStatusCode.OK);
+    }
+
+    [Fact]
+    public async Task Gateway_ReturnsNotFound_ForUnknownRoute()
+    {
+        // Act
+        var response = await _fixture.GatewayClient.GetAsync("/unknown/route");
+
+        // Assert
+        response.StatusCode.Should().Be(HttpStatusCode.NotFound);
+    }
+}