diff --git a/spec/active_record/oracle_enhanced/type/custom_spec.rb b/spec/active_record/oracle_enhanced/type/custom_spec.rb
index e7e50a84c..bcc04feda 100644
--- a/spec/active_record/oracle_enhanced/type/custom_spec.rb
+++ b/spec/active_record/oracle_enhanced/type/custom_spec.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require "base64"
+
 describe "OracleEnhancedAdapter custom types handling" do
   include SchemaSpecHelper