Better handling of allOf in request body (#16991)

* better handling of allOf in request body, add tests

* additional checks

* fix description

samples/client/echo_api/ruby-httpx/lib/openapi_client/api/body_api.rb

@@ -209,6 +209,70 @@ module OpenapiClient
       return data, status_code, headers
     end
 
+    # Test body parameter(s)
+    # Test body parameter(s)
+    # @param [Hash] opts the optional parameters
+    # @option opts [Pet] :pet Pet object that needs to be added to the store
+    # @return [Pet]
+    def test_echo_body_all_of_pet(opts = {})
+      data, _status_code, _headers = test_echo_body_all_of_pet_with_http_info(opts)
+      data
+    end
+
+    # Test body parameter(s)
+    # Test body parameter(s)
+    # @param [Hash] opts the optional parameters
+    # @option opts [Pet] :pet Pet object that needs to be added to the store
+    # @return [Array<(Pet, Integer, Hash)>] Pet data, response status code and response headers
+    def test_echo_body_all_of_pet_with_http_info(opts = {})
+      if @api_client.config.debugging
+        @api_client.config.logger.debug 'Calling API: BodyApi.test_echo_body_all_of_pet ...'
+      end
+      # resource path
+      local_var_path = '/echo/body/allOf/Pet'
+
+      # query parameters
+      query_params = opts[:query_params] || {}
+
+      # header parameters
+      header_params = opts[:header_params] || {}
+      # HTTP header 'Accept' (if needed)
+      header_params['Accept'] = @api_client.select_header_accept(['application/json'])
+      # HTTP header 'Content-Type'
+      content_type = @api_client.select_header_content_type(['application/json'])
+      if !content_type.nil?
+          header_params['Content-Type'] = content_type
+      end
+
+      # form parameters
+      form_params = opts[:form_params] || {}
+
+      # http body (model)
+      post_body = opts[:debug_body] || @api_client.object_to_http_body(opts[:'pet'])
+
+      # return_type
+      return_type = opts[:debug_return_type] || 'Pet'
+
+      # auth_names
+      auth_names = opts[:debug_auth_names] || []
+
+      new_options = opts.merge(
+        :operation => :"BodyApi.test_echo_body_all_of_pet",
+        :header_params => header_params,
+        :query_params => query_params,
+        :form_params => form_params,
+        :body => post_body,
+        :auth_names => auth_names,
+        :return_type => return_type
+      )
+
+      data, status_code, headers = @api_client.call_api(:POST, local_var_path, new_options)
+      if @api_client.config.debugging
+        @api_client.config.logger.debug "API called: BodyApi#test_echo_body_all_of_pet\nData: #{data.inspect}\nStatus code: #{status_code}\nHeaders: #{headers}"
+      end
+      return data, status_code, headers
+    end
+
     # Test free form object
     # Test free form object
     # @param [Hash] opts the optional parameters