fix: failed to convert active model type to spanner type under certain condition (#299)

* fix: failed to convert active model type to spanner type. under certain condition

Added support for the case where a DelegateClass such as ActiveRecord::AttributeMethods::TimeZoneConversion::TimeZoneConverter is passed to type.

* test: add test for DelegateClass conversions

---------

Co-authored-by: Knut Olav Løite <koloite@gmail.com>

Author: ruzia

lib/active_record/type/spanner/spanner_active_record_converter.rb

@@ -23,6 +23,9 @@ def self.serialize_with_transaction_isolation_level type, value, isolation_level
         ##
         # Converts an ActiveModel::Type to a Spanner type code.
         def self.convert_active_model_type_to_spanner type # rubocop:disable Metrics/CyclomaticComplexity
+          # Unwrap the underlying object if the type is a DelegateClass.
+          type = type.__getobj__ if type.respond_to? :__getobj__
+
           case type
           when NilClass then nil
           when ActiveModel::Type::Integer, ActiveModel::Type::BigInteger then :INT64

test/activerecord_spanner_mock_server/spanner_active_record_with_mock_server_test.rb

@@ -306,6 +306,23 @@ def test_create_singer_with_last_performance_as_time
       assert_equal "2021-05-12T08:30:00.000000000Z", request.params["p3"]
     end
 
+    def test_create_singer_with_time_zone_aware_attributes
+      Singer.time_zone_aware_attributes=true
+
+      insert_sql = "INSERT INTO `singers` (`first_name`, `last_name`, `last_performance`, `id`) VALUES (@p1, @p2, @p3, @p4)"
+      @mock.put_statement_result insert_sql, StatementResult.new(1)
+
+      Singer.transaction do
+        Singer.create(first_name: "Dave", last_name: "Allison", last_performance: ::Time.parse("2021-05-12T10:30:00+02:00"))
+      end
+
+      request = @mock.requests.select {|req| req.is_a?(Google::Cloud::Spanner::V1::ExecuteSqlRequest) && req.sql == insert_sql }.first
+      assert_equal :TIMESTAMP, request.param_types["p3"].code
+      assert_equal "2021-05-12T08:30:00.000000000Z", request.params["p3"]
+    ensure
+      Singer.time_zone_aware_attributes=false
+    end
+
     def test_create_singer_with_last_performance_as_non_iso_string
       insert_sql = "INSERT INTO `singers` (`first_name`, `last_name`, `last_performance`, `id`) VALUES (@p1, @p2, @p3, @p4)"
       @mock.put_statement_result insert_sql, StatementResult.new(1)