Added tests

Author: Tyler-R-Kendrick

src/ModelContextProtocol/Server/McpServer.cs

@@ -185,14 +185,28 @@ private void SetResourcesHandler(McpServerOptions options)
 
         var listResourcesHandler = resourcesCapability.ListResourcesHandler;
         var listResourceTemplatesHandler = resourcesCapability.ListResourceTemplatesHandler;
+        var resourceCollection = resourcesCapability.ResourceCollection;
 
         if ((listResourcesHandler is not { } && listResourceTemplatesHandler is not { }) ||
             resourcesCapability.ReadResourceHandler is not { } readResourceHandler)
         {
             throw new McpException("Resources capability was enabled, but ListResources and/or ReadResource handlers were not specified.");
         }
 
-        listResourcesHandler ??= (static (_, _) => Task.FromResult(new ListResourcesResult()));
+        var originalListResourcesHandler = listResourcesHandler;
+        listResourcesHandler = async (request, cancellationToken) =>
+        {
+            ListResourcesResult result = originalListResourcesHandler is not null ?
+                await originalListResourcesHandler(request, cancellationToken).ConfigureAwait(false) :
+                new();
+
+            if (request.Params?.Cursor is null && resourceCollection is not null)
+            {
+                result.Resources.AddRange(resourceCollection.Select(t => t.ProtocolResource));
+            }
+
+            return result;
+        };
 
         RequestHandlers.Set(
             RequestMethods.ResourcesList,

tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsResourcesTests.cs

@@ -0,0 +1,110 @@
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.FileProviders;
+using Microsoft.Extensions.Options;
+using ModelContextProtocol.Client;
+using ModelContextProtocol.Protocol.Messages;
+using ModelContextProtocol.Server;
+
+namespace ModelContextProtocol.Tests.Configuration;
+
+public class McpServerBuilderExtensionsResourcesTests(ITestOutputHelper testOutputHelper)
+    : ClientServerTestBase(testOutputHelper)
+{
+    protected override void ConfigureServices(ServiceCollection services, IMcpServerBuilder mcpServerBuilder)
+    {
+        mcpServerBuilder = mcpServerBuilder.WithResources(
+            new FakeFileInfo()
+            {
+                Name = "test",
+                PhysicalPath = "test.txt",
+                Length = 0,
+            },
+            new FakeFileInfo()
+            {
+                Name = "test2",
+                PhysicalPath = "test2.txt",
+                Length = 0,
+            });
+        base.ConfigureServices(services, mcpServerBuilder);
+    }
+
+    private class FakeFileInfo : IFileInfo
+    {
+        public string Name { get; set; } = "test.txt";
+        public long Length { get; set; } = 0;
+        public bool Exists => true;
+
+        public string? PhysicalPath { get; set; } = "test.txt";
+
+        public DateTimeOffset LastModified { get; set; } = DateTimeOffset.UtcNow;
+
+        public bool IsDirectory => false;
+
+        public Stream CreateReadStream() => new MemoryStream();
+    }
+
+    [Fact]
+    public void Adds_Resources_To_Server()
+    {        
+        var serverOptions = ServiceProvider.GetRequiredService<IOptions<McpServerOptions>>().Value;
+        var resources = serverOptions?.Capabilities?.Resources?.ResourceCollection;
+        Assert.NotNull(resources);
+        Assert.Equal(2, resources.Count);
+        Assert.Equal("test.txt", resources["test"].Name);
+        Assert.Equal("test2.txt", resources["test2"].Name);
+    }
+
+    [Fact]
+    public async Task Can_List_Resources()
+    {
+        // Arrange
+        var token = TestContext.Current.CancellationToken;
+        var client = await CreateMcpClientForServer();
+
+        // Act
+        var resources = await client.ListResourcesAsync(token);
+
+        // Assert
+        Assert.NotNull(resources);
+        Assert.Equal(2, resources.Count);
+    }
+
+    [Fact]
+    public async Task Can_Be_Notified_Of_ResourceList_Changes()
+    {
+        // Arrange
+        var token = TestContext.Current.CancellationToken;
+        var client = await CreateMcpClientForServer();
+        var serverOptions = ServiceProvider
+            .GetRequiredService<IOptions<McpServerOptions>>()
+            .Value;
+        TaskCompletionSource<JsonRpcNotification> changeReceived = new();
+        client.RegisterNotificationHandler(
+            NotificationMethods.ResourceListChangedNotification,
+            (notification, token) =>
+            {
+                changeReceived.SetResult(notification);
+                return changeReceived.Task;
+            });
+
+        // Act
+        var resources = await client.ListResourcesAsync(token);
+        Assert.NotNull(resources);
+        Assert.Equal(2, resources.Count);
+
+        serverOptions?.Capabilities?.Resources?.ResourceCollection?.Add(new McpServerResource
+        {
+            ProtocolResource = new()
+            {
+                Name = "new resource",
+                Uri = "test3.txt",
+            },
+        });
+
+        // Assert
+        await changeReceived.Task.WaitAsync(TimeSpan.FromSeconds(3), token);
+        var updatedResources = await client.ListResourcesAsync(token);
+        Assert.NotNull(updatedResources);
+        Assert.Equal(3, updatedResources.Count);
+    }
+}