Add serialization round-trip tests for notification params and capability types

Add 10 new test files covering serialization for:
- ResourceListChangedNotificationParams
- RootsListChangedNotificationParams
- PromptListChangedNotificationParams
- ToolListChangedNotificationParams
- SamplingCapability
- RootsCapability
- PromptsCapability
- ResourcesCapability
- ToolsCapability
- ElicitationCapability

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Copilot

tests/ModelContextProtocol.Tests/Protocol/ElicitationCapabilityTests.cs

@@ -0,0 +1,38 @@
+using ModelContextProtocol.Protocol;
+using System.Text.Json;
+
+namespace ModelContextProtocol.Tests.Protocol;
+
+public static class ElicitationCapabilityTests
+{
+    [Fact]
+    public static void ElicitationCapability_SerializationRoundTrip_PreservesAllProperties()
+    {
+        var original = new ElicitationCapability
+        {
+            Form = new FormElicitationCapability(),
+            Url = new UrlElicitationCapability()
+        };
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<ElicitationCapability>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.NotNull(deserialized.Form);
+        Assert.NotNull(deserialized.Url);
+    }
+
+    [Fact]
+    public static void ElicitationCapability_SerializationRoundTrip_WithMinimalProperties()
+    {
+        var original = new ElicitationCapability();
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<ElicitationCapability>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        // The custom converter defaults Form to non-null when both Form and Url are null for backward compatibility
+        Assert.NotNull(deserialized.Form);
+        Assert.Null(deserialized.Url);
+    }
+}

tests/ModelContextProtocol.Tests/Protocol/PromptListChangedNotificationParamsTests.cs

@@ -0,0 +1,35 @@
+using ModelContextProtocol.Protocol;
+using System.Text.Json;
+using System.Text.Json.Nodes;
+
+namespace ModelContextProtocol.Tests.Protocol;
+
+public static class PromptListChangedNotificationParamsTests
+{
+    [Fact]
+    public static void PromptListChangedNotificationParams_SerializationRoundTrip_PreservesAllProperties()
+    {
+        var original = new PromptListChangedNotificationParams
+        {
+            Meta = new JsonObject { ["key"] = "value" }
+        };
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<PromptListChangedNotificationParams>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.NotNull(deserialized.Meta);
+    }
+
+    [Fact]
+    public static void PromptListChangedNotificationParams_SerializationRoundTrip_WithMinimalProperties()
+    {
+        var original = new PromptListChangedNotificationParams();
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<PromptListChangedNotificationParams>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.Null(deserialized.Meta);
+    }
+}

tests/ModelContextProtocol.Tests/Protocol/PromptsCapabilityTests.cs

@@ -0,0 +1,34 @@
+using ModelContextProtocol.Protocol;
+using System.Text.Json;
+
+namespace ModelContextProtocol.Tests.Protocol;
+
+public static class PromptsCapabilityTests
+{
+    [Fact]
+    public static void PromptsCapability_SerializationRoundTrip_PreservesAllProperties()
+    {
+        var original = new PromptsCapability
+        {
+            ListChanged = true
+        };
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<PromptsCapability>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.True(deserialized.ListChanged);
+    }
+
+    [Fact]
+    public static void PromptsCapability_SerializationRoundTrip_WithMinimalProperties()
+    {
+        var original = new PromptsCapability();
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<PromptsCapability>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.Null(deserialized.ListChanged);
+    }
+}

tests/ModelContextProtocol.Tests/Protocol/ResourceListChangedNotificationParamsTests.cs

@@ -0,0 +1,35 @@
+using ModelContextProtocol.Protocol;
+using System.Text.Json;
+using System.Text.Json.Nodes;
+
+namespace ModelContextProtocol.Tests.Protocol;
+
+public static class ResourceListChangedNotificationParamsTests
+{
+    [Fact]
+    public static void ResourceListChangedNotificationParams_SerializationRoundTrip_PreservesAllProperties()
+    {
+        var original = new ResourceListChangedNotificationParams
+        {
+            Meta = new JsonObject { ["key"] = "value" }
+        };
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<ResourceListChangedNotificationParams>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.NotNull(deserialized.Meta);
+    }
+
+    [Fact]
+    public static void ResourceListChangedNotificationParams_SerializationRoundTrip_WithMinimalProperties()
+    {
+        var original = new ResourceListChangedNotificationParams();
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<ResourceListChangedNotificationParams>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.Null(deserialized.Meta);
+    }
+}

tests/ModelContextProtocol.Tests/Protocol/ResourcesCapabilityTests.cs

@@ -0,0 +1,37 @@
+using ModelContextProtocol.Protocol;
+using System.Text.Json;
+
+namespace ModelContextProtocol.Tests.Protocol;
+
+public static class ResourcesCapabilityTests
+{
+    [Fact]
+    public static void ResourcesCapability_SerializationRoundTrip_PreservesAllProperties()
+    {
+        var original = new ResourcesCapability
+        {
+            Subscribe = true,
+            ListChanged = true
+        };
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<ResourcesCapability>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.True(deserialized.Subscribe);
+        Assert.True(deserialized.ListChanged);
+    }
+
+    [Fact]
+    public static void ResourcesCapability_SerializationRoundTrip_WithMinimalProperties()
+    {
+        var original = new ResourcesCapability();
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<ResourcesCapability>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.Null(deserialized.Subscribe);
+        Assert.Null(deserialized.ListChanged);
+    }
+}

tests/ModelContextProtocol.Tests/Protocol/RootsCapabilityTests.cs

@@ -0,0 +1,34 @@
+using ModelContextProtocol.Protocol;
+using System.Text.Json;
+
+namespace ModelContextProtocol.Tests.Protocol;
+
+public static class RootsCapabilityTests
+{
+    [Fact]
+    public static void RootsCapability_SerializationRoundTrip_PreservesAllProperties()
+    {
+        var original = new RootsCapability
+        {
+            ListChanged = true
+        };
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<RootsCapability>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.True(deserialized.ListChanged);
+    }
+
+    [Fact]
+    public static void RootsCapability_SerializationRoundTrip_WithMinimalProperties()
+    {
+        var original = new RootsCapability();
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<RootsCapability>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.Null(deserialized.ListChanged);
+    }
+}

tests/ModelContextProtocol.Tests/Protocol/RootsListChangedNotificationParamsTests.cs

@@ -0,0 +1,35 @@
+using ModelContextProtocol.Protocol;
+using System.Text.Json;
+using System.Text.Json.Nodes;
+
+namespace ModelContextProtocol.Tests.Protocol;
+
+public static class RootsListChangedNotificationParamsTests
+{
+    [Fact]
+    public static void RootsListChangedNotificationParams_SerializationRoundTrip_PreservesAllProperties()
+    {
+        var original = new RootsListChangedNotificationParams
+        {
+            Meta = new JsonObject { ["key"] = "value" }
+        };
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<RootsListChangedNotificationParams>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.NotNull(deserialized.Meta);
+    }
+
+    [Fact]
+    public static void RootsListChangedNotificationParams_SerializationRoundTrip_WithMinimalProperties()
+    {
+        var original = new RootsListChangedNotificationParams();
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<RootsListChangedNotificationParams>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.Null(deserialized.Meta);
+    }
+}

tests/ModelContextProtocol.Tests/Protocol/SamplingCapabilityTests.cs

@@ -0,0 +1,37 @@
+using ModelContextProtocol.Protocol;
+using System.Text.Json;
+
+namespace ModelContextProtocol.Tests.Protocol;
+
+public static class SamplingCapabilityTests
+{
+    [Fact]
+    public static void SamplingCapability_SerializationRoundTrip_PreservesAllProperties()
+    {
+        var original = new SamplingCapability
+        {
+            Context = new SamplingContextCapability(),
+            Tools = new SamplingToolsCapability()
+        };
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<SamplingCapability>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.NotNull(deserialized.Context);
+        Assert.NotNull(deserialized.Tools);
+    }
+
+    [Fact]
+    public static void SamplingCapability_SerializationRoundTrip_WithMinimalProperties()
+    {
+        var original = new SamplingCapability();
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<SamplingCapability>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.Null(deserialized.Context);
+        Assert.Null(deserialized.Tools);
+    }
+}

tests/ModelContextProtocol.Tests/Protocol/ToolListChangedNotificationParamsTests.cs

@@ -0,0 +1,35 @@
+using ModelContextProtocol.Protocol;
+using System.Text.Json;
+using System.Text.Json.Nodes;
+
+namespace ModelContextProtocol.Tests.Protocol;
+
+public static class ToolListChangedNotificationParamsTests
+{
+    [Fact]
+    public static void ToolListChangedNotificationParams_SerializationRoundTrip_PreservesAllProperties()
+    {
+        var original = new ToolListChangedNotificationParams
+        {
+            Meta = new JsonObject { ["key"] = "value" }
+        };
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<ToolListChangedNotificationParams>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.NotNull(deserialized.Meta);
+    }
+
+    [Fact]
+    public static void ToolListChangedNotificationParams_SerializationRoundTrip_WithMinimalProperties()
+    {
+        var original = new ToolListChangedNotificationParams();
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<ToolListChangedNotificationParams>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.Null(deserialized.Meta);
+    }
+}

tests/ModelContextProtocol.Tests/Protocol/ToolsCapabilityTests.cs

@@ -0,0 +1,34 @@
+using ModelContextProtocol.Protocol;
+using System.Text.Json;
+
+namespace ModelContextProtocol.Tests.Protocol;
+
+public static class ToolsCapabilityTests
+{
+    [Fact]
+    public static void ToolsCapability_SerializationRoundTrip_PreservesAllProperties()
+    {
+        var original = new ToolsCapability
+        {
+            ListChanged = true
+        };
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<ToolsCapability>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.True(deserialized.ListChanged);
+    }
+
+    [Fact]
+    public static void ToolsCapability_SerializationRoundTrip_WithMinimalProperties()
+    {
+        var original = new ToolsCapability();
+
+        string json = JsonSerializer.Serialize(original, McpJsonUtilities.DefaultOptions);
+        var deserialized = JsonSerializer.Deserialize<ToolsCapability>(json, McpJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserialized);
+        Assert.Null(deserialized.ListChanged);
+    }
+}