Add Conformance tests for the server (#983)

tests/ModelContextProtocol.ConformanceServer/Prompts/ConformancePrompts.cs

@@ -0,0 +1,67 @@
+using ModelContextProtocol.Server;
+using ModelContextProtocol.Protocol;
+using Microsoft.Extensions.AI;
+using System.ComponentModel;
+
+namespace ConformanceServer.Prompts;
+
+public class ConformancePrompts
+{
+    // Sample base64 encoded 1x1 red PNG pixel for testing
+    private const string TestImageBase64 =
+      "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8DwHwAFBQIAX8jx0gAAAABJRU5ErkJggg==";
+
+    [McpServerPrompt(Name = "test_simple_prompt"), Description("Simple prompt without arguments")]
+    public static string SimplePrompt() => "This is a simple prompt without arguments";
+
+    [McpServerPrompt(Name = "test_prompt_with_arguments"), Description("Parameterized prompt")]
+    public static string ParameterizedPrompt(
+        [Description("First test argument")] string arg1,
+        [Description("Second test argument")] string arg2)
+    {
+        return $"Prompt with arguments: arg1={arg1}, arg2={arg2}";
+    }
+
+    [McpServerPrompt(Name = "test_prompt_with_embedded_resource"), Description("Prompt with embedded resource")]
+    public static IEnumerable<PromptMessage> PromptWithEmbeddedResource(
+        [Description("URI of the resource to embed")] string resourceUri)
+    {
+        return [
+            new PromptMessage
+            {
+                Role = Role.User,
+                Content = new EmbeddedResourceBlock
+                {
+                    Resource = new TextResourceContents
+                    {
+                        Uri = resourceUri,
+                        Text = "Embedded resource content for testing.",
+                        MimeType = "text/plain"
+                    }
+                }
+            },
+            new PromptMessage { Role = Role.User, Content = new TextContentBlock { Text = "Please process the embedded resource above." } },
+        ];
+    }
+
+    [McpServerPrompt(Name = "test_prompt_with_image"), Description("Prompt with image")]
+    public static IEnumerable<PromptMessage> PromptWithImage()
+    {
+        return [
+            new PromptMessage
+            {
+                Role = Role.User,
+                Content = new ImageContentBlock
+                {
+                    MimeType = "image/png",
+                    Data = TestImageBase64
+                }
+            },
+            new PromptMessage
+            {
+                Role = Role.User,
+                Content = new TextContentBlock { Text = "Please analyze the image above." }
+            },
+        ];
+    }
+}