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/InventoryEndpointTests.cs

@@ -0,0 +1,74 @@
+using System.Net;
+using System.Text.Json;
+using FluentAssertions;
+using Xunit;
+
+namespace Examples.Integration.Tests;
+
+/// <summary>
+/// Integration tests for the Inventory microservice endpoints.
+/// </summary>
+public sealed class InventoryEndpointTests : IClassFixture<GatewayFixture>
+{
+    private readonly GatewayFixture _fixture;
+
+    public InventoryEndpointTests(GatewayFixture fixture)
+    {
+        _fixture = fixture;
+    }
+
+    [Fact]
+    public async Task ListItems_WithoutFilters_ReturnsAllItems()
+    {
+        // Act
+        var response = await _fixture.GatewayClient.GetAsync("/items");
+
+        // Assert
+        response.StatusCode.Should().Be(HttpStatusCode.OK);
+        var content = await response.Content.ReadAsStringAsync();
+        content.Should().Contain("items");
+        content.Should().Contain("totalCount");
+    }
+
+    [Fact]
+    public async Task ListItems_WithCategoryFilter_ReturnsFilteredItems()
+    {
+        // Act
+        var response = await _fixture.GatewayClient.GetAsync("/items?category=widgets");
+
+        // Assert
+        response.StatusCode.Should().Be(HttpStatusCode.OK);
+        var content = await response.Content.ReadAsStringAsync();
+        content.Should().Contain("widgets");
+    }
+
+    [Fact]
+    public async Task ListItems_WithPagination_ReturnsPaginatedResponse()
+    {
+        // Act
+        var response = await _fixture.GatewayClient.GetAsync("/items?page=1&pageSize=10");
+
+        // Assert
+        response.StatusCode.Should().Be(HttpStatusCode.OK);
+        var content = await response.Content.ReadAsStringAsync();
+        content.Should().Contain("\"page\":1");
+        content.Should().Contain("\"pageSize\":10");
+    }
+
+    [Fact]
+    public async Task GetItem_WithValidSku_ReturnsItem()
+    {
+        // Arrange
+        var sku = "SKU-001";
+
+        // Act
+        var response = await _fixture.GatewayClient.GetAsync($"/items/{sku}");
+
+        // Assert
+        response.StatusCode.Should().Be(HttpStatusCode.OK);
+        var content = await response.Content.ReadAsStringAsync();
+        content.Should().Contain(sku);
+        content.Should().Contain("name");
+        content.Should().Contain("quantityOnHand");
+    }
+}