Adding public API test coverage for Microsoft.Extensions.ServiceDiscovery.Yarp

src/Microsoft.Extensions.ServiceDiscovery.Yarp/ServiceDiscoveryReverseProxyServiceCollectionExtensions.cs

@@ -17,6 +17,8 @@ public static class ServiceDiscoveryReverseProxyServiceCollectionExtensions
     /// </summary>
     public static IReverseProxyBuilder AddServiceDiscoveryDestinationResolver(this IReverseProxyBuilder builder)
     {
+        ArgumentNullException.ThrowIfNull(builder);
+
         builder.Services.AddServiceDiscoveryCore();
         builder.Services.AddSingleton<IDestinationResolver, ServiceDiscoveryDestinationResolver>();
         return builder;
@@ -27,6 +29,8 @@ public static IReverseProxyBuilder AddServiceDiscoveryDestinationResolver(this I
     /// </summary>
     public static IServiceCollection AddHttpForwarderWithServiceDiscovery(this IServiceCollection services)
     {
+        ArgumentNullException.ThrowIfNull(services);
+
         return services.AddHttpForwarder().AddServiceDiscoveryForwarderFactory();
     }
 
@@ -35,6 +39,8 @@ public static IServiceCollection AddHttpForwarderWithServiceDiscovery(this IServ
     /// </summary>
     public static IServiceCollection AddServiceDiscoveryForwarderFactory(this IServiceCollection services)
     {
+        ArgumentNullException.ThrowIfNull(services);
+
         services.AddServiceDiscoveryCore();
         services.AddSingleton<IForwarderHttpClientFactory, ServiceDiscoveryForwarderHttpClientFactory>();
         return services;

tests/Microsoft.Extensions.ServiceDiscovery.Yarp.Tests/YarpServiceDiscoveryPublicApiTests.cs

@@ -0,0 +1,45 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.Extensions.DependencyInjection;
+using Xunit;
+
+namespace Microsoft.Extensions.ServiceDiscovery.Yarp.Tests;
+
+#pragma warning disable IDE0200
+
+public class YarpServiceDiscoveryPublicApiTests
+{
+    [Fact]
+    public void AddServiceDiscoveryDestinationResolverShouldThrowWhenBuilderIsNull()
+    {
+        IReverseProxyBuilder builder = null!;
+
+        var action = () => builder.AddServiceDiscoveryDestinationResolver();
+
+        var exception = Assert.Throws<ArgumentNullException>(action);
+        Assert.Equal(nameof(builder), exception.ParamName);
+    }
+
+    [Fact]
+    public void AddHttpForwarderWithServiceDiscoveryShouldThrowWhenServicesIsNull()
+    {
+        IServiceCollection services = null!;
+
+        var action = () => services.AddHttpForwarderWithServiceDiscovery();
+
+        var exception = Assert.Throws<ArgumentNullException>(action);
+        Assert.Equal(nameof(services), exception.ParamName);
+    }
+
+    [Fact]
+    public void AddServiceDiscoveryForwarderFactoryShouldThrowWhenServicesIsNull()
+    {
+        IServiceCollection services = null!;
+
+        var action = () => services.AddServiceDiscoveryForwarderFactory();
+
+        var exception = Assert.Throws<ArgumentNullException>(action);
+        Assert.Equal(nameof(services), exception.ParamName);
+    }
+}