Validate ToolCall Args against Schema

(cherry picked from commit eeb287117535dfb43785704171625323f01d5bda)

test/mcp/tool/input_schema_test.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "test_helper"
+require "mcp/tool/input_schema"
 
 module MCP
   class Tool
@@ -27,6 +28,29 @@ module MCP
         input_schema = InputSchema.new(properties: { message: { type: "string" } }, required: [:message])
         assert_empty input_schema.missing_required_arguments({ message: "Hello, world!" })
       end
+
+      test "valid schema initialization" do
+        schema = InputSchema.new(properties: { foo: { type: "string" } }, required: [:foo])
+        assert_equal({ type: "object", properties: { foo: { type: "string" } }, required: [:foo] }, schema.to_h)
+      end
+
+      test "invalid schema raises argument error" do
+        assert_raises(ArgumentError) do
+          InputSchema.new(properties: { foo: { type: "invalid_type" } }, required: [:foo])
+        end
+      end
+
+      test "validate arguments with valid data" do
+        schema = InputSchema.new(properties: { foo: { type: "string" } }, required: [:foo])
+        assert_nil(schema.validate_arguments({ foo: "bar" }))
+      end
+
+      test "validate arguments with invalid data" do
+        schema = InputSchema.new(properties: { foo: { type: "string" } }, required: [:foo])
+        assert_raises(InputSchema::ValidationError) do
+          schema.validate_arguments({ foo: 123 })
+        end
+      end
     end
   end
 end