Encapsulate enrichment actions, add tests

app/models/plaid_item.rb

@@ -77,14 +77,14 @@ class PlaidItem < ApplicationRecord
         category = alias_matcher.match(transaction.plaid_category_detailed)
 
         if category.present?
-          PlaidItem.transaction do
-            transaction.log_enrichment!(
-              attribute_name: "category_id",
-              attribute_value: category.id,
-              source: "plaid"
-            )
-            transaction.set_category!(category)
+          # Matcher could either return a string or a Category object
+          user_category = if category.is_a?(String)
+            family.categories.find_or_create_by!(name: category)
+          else
+            category
           end
+
+          transaction.enrich_attribute(:category_id, user_category.id, source: "plaid")
         end
       end
     end