Only run limit-validation tests when the limit exists

SQLite and PostgreSQL won't add a default limit of 255 for string types

activerecord/lib/active_record/encryption/encryptable_record.rb

@@ -128,7 +128,7 @@ def preserve_original_encrypted(name)
           end
 
           def validate_column_size(attribute_name)
-            if table_exists? && limit = connection.schema_cache.columns_hash(table_name)[attribute_name.to_s]&.limit
+            if table_exists? && limit = columns_hash[attribute_name.to_s]&.limit
               validates_length_of attribute_name, maximum: limit
             end
           end

activerecord/test/cases/encryption/encryptable_record_test.rb

@@ -215,7 +215,8 @@ class ActiveRecord::Encryption::EncryptableRecordTest < ActiveRecord::TestCase
     assert_equal "Stephen King", author.name
   end
 
-  unless current_adapter?(:SQLite3Adapter)
+  # Only run for adapters that add a default string limit when not provided (MySQL, 255)
+  if EncryptedAuthor.columns_hash["name"].limit
     # No column limits in SQLLite
     test "validate column sizes" do
       assert EncryptedAuthor.new(name: "jorge").valid?