Add tools support to sampling (#976)

tests/ModelContextProtocol.Tests/AIContentExtensionsTests.cs

@@ -25,4 +25,127 @@ public class AIContentExtensionsTests
         JsonElement result = Assert.IsType<JsonElement>(frc.Result);
         Assert.Contains("This is a test message.", result.ToString());
     }
+
+    [Fact]
+    public void ToAIContent_ConvertsToolUseContentBlock()
+    {
+        Dictionary<string, object?> inputDict = new() { ["city"] = "Paris", ["units"] = "metric" };
+        ToolUseContentBlock toolUse = new()
+        {
+            Id = "call_abc123",
+            Name = "get_weather",
+            Input = JsonSerializer.SerializeToElement(inputDict, McpJsonUtilities.DefaultOptions)
+        };
+
+        AIContent? aiContent = toolUse.ToAIContent();
+
+        var functionCall = Assert.IsType<FunctionCallContent>(aiContent);
+        Assert.Equal("call_abc123", functionCall.CallId);
+        Assert.Equal("get_weather", functionCall.Name);
+        Assert.NotNull(functionCall.Arguments);
+        
+        var cityArg = Assert.IsType<JsonElement>(functionCall.Arguments["city"]);
+        Assert.Equal("Paris", cityArg.GetString());
+        var unitsArg = Assert.IsType<JsonElement>(functionCall.Arguments["units"]);
+        Assert.Equal("metric", unitsArg.GetString());
+    }
+
+    [Fact]
+    public void ToAIContent_ConvertsToolResultContentBlock()
+    {
+        ToolResultContentBlock toolResult = new()
+        {
+            ToolUseId = "call_abc123",
+            Content = [new TextContentBlock { Text = "Weather: 18°C" }],
+            IsError = false
+        };
+
+        AIContent? aiContent = toolResult.ToAIContent();
+
+        var functionResult = Assert.IsType<FunctionResultContent>(aiContent);
+        Assert.Equal("call_abc123", functionResult.CallId);
+        Assert.Null(functionResult.Exception);
+        Assert.NotNull(functionResult.Result);
+    }
+
+    [Fact]
+    public void ToAIContent_ConvertsToolResultContentBlockWithError()
+    {
+        ToolResultContentBlock toolResult = new()
+        {
+            ToolUseId = "call_abc123",
+            Content = [new TextContentBlock { Text = "Error: Invalid city" }],
+            IsError = true
+        };
+
+        AIContent? aiContent = toolResult.ToAIContent();
+
+        var functionResult = Assert.IsType<FunctionResultContent>(aiContent);
+        Assert.Equal("call_abc123", functionResult.CallId);
+        Assert.NotNull(functionResult.Exception);
+    }
+
+    [Fact]
+    public void ToAIContent_ConvertsToolResultWithMultipleContent()
+    {
+        ToolResultContentBlock toolResult = new()
+        {
+            ToolUseId = "call_123",
+            Content =
+            [
+                new TextContentBlock { Text = "Text result" },
+                new ImageContentBlock { Data = Convert.ToBase64String([1, 2, 3]), MimeType = "image/png" }
+            ]
+        };
+
+        AIContent? aiContent = toolResult.ToAIContent();
+
+        var functionResult = Assert.IsType<FunctionResultContent>(aiContent);
+        Assert.Equal("call_123", functionResult.CallId);
+        
+        var resultList = Assert.IsAssignableFrom<IList<AIContent>>(functionResult.Result);
+        Assert.Equal(2, resultList.Count);
+        Assert.IsType<TextContent>(resultList[0]);
+        Assert.IsType<DataContent>(resultList[1]);
+    }
+
+    [Fact]
+    public void ToAIContent_ToolUseToFunctionCallRoundTrip()
+    {
+        Dictionary<string, object?> inputDict = new() { ["param1"] = "value1", ["param2"] = 42 };
+        ToolUseContentBlock original = new()
+        {
+            Id = "call_123",
+            Name = "test_tool",
+            Input = JsonSerializer.SerializeToElement(inputDict, McpJsonUtilities.DefaultOptions)
+        };
+
+        var functionCall = Assert.IsType<FunctionCallContent>(original.ToAIContent());
+
+        Assert.Equal("call_123", functionCall.CallId);
+        Assert.Equal("test_tool", functionCall.Name);
+        Assert.NotNull(functionCall.Arguments);
+        
+        var param1 = Assert.IsType<JsonElement>(functionCall.Arguments["param1"]);
+        Assert.Equal("value1", param1.GetString());
+        var param2 = Assert.IsType<JsonElement>(functionCall.Arguments["param2"]);
+        Assert.Equal(42, param2.GetInt32());
+    }
+
+    [Fact]
+    public void ToAIContent_ToolResultToFunctionResultRoundTrip()
+    {
+        ToolResultContentBlock original = new()
+        {
+            ToolUseId = "call_123",
+            Content = [new TextContentBlock { Text = "Result" }, new TextContentBlock { Text = "More data" }],
+            IsError = false
+        };
+
+        var functionResult = Assert.IsType<FunctionResultContent>(original.ToAIContent());
+
+        Assert.Equal("call_123", functionResult.CallId);
+        Assert.False(functionResult.Exception != null);
+        Assert.NotNull(functionResult.Result);
+    }
 }