Add coverage for StatusTrend and PreviewCardTrend models, add locales class method to RankedTrend (#32688)

app/controllers/admin/trends/links_controller.rb

@@ -4,7 +4,7 @@ class Admin::Trends::LinksController < Admin::BaseController
   def index
     authorize :preview_card, :review?
 
-    @locales       = PreviewCardTrend.pluck('distinct language')
+    @locales       = PreviewCardTrend.locales
     @preview_cards = filtered_preview_cards.page(params[:page])
     @form          = Trends::PreviewCardBatch.new
   end

app/controllers/admin/trends/statuses_controller.rb

@@ -4,7 +4,7 @@ class Admin::Trends::StatusesController < Admin::BaseController
   def index
     authorize [:admin, :status], :review?
 
-    @locales  = StatusTrend.pluck('distinct language')
+    @locales  = StatusTrend.locales
     @statuses = filtered_statuses.page(params[:page])
     @form     = Trends::StatusBatch.new
   end

app/models/concerns/ranked_trend.rb

@@ -9,6 +9,10 @@ module RankedTrend
   end
 
   class_methods do
+    def locales
+      distinct.pluck(:language)
+    end
+
     def recalculate_ordered_rank
       connection
         .exec_update(<<~SQL.squish)

app/models/trends/links.rb

@@ -85,7 +85,7 @@ class Trends::Links < Trends::Base
   end
 
   def request_review
-    PreviewCardTrend.pluck('distinct language').flat_map do |language|
+    PreviewCardTrend.locales.flat_map do |language|
       score_at_threshold  = PreviewCardTrend.where(language: language).allowed.by_rank.ranked_below(options[:review_threshold]).first&.score || 0
       preview_card_trends = PreviewCardTrend.where(language: language).not_allowed.joins(:preview_card)
 

app/models/trends/statuses.rb

@@ -78,7 +78,7 @@ class Trends::Statuses < Trends::Base
   end
 
   def request_review
-    StatusTrend.pluck('distinct language').flat_map do |language|
+    StatusTrend.locales.flat_map do |language|
       score_at_threshold = StatusTrend.where(language: language, allowed: true).by_rank.ranked_below(options[:review_threshold]).first&.score || 0
       status_trends      = StatusTrend.where(language: language, allowed: false).joins(:status).includes(status: :account)