ヘルプを Wiki から分離 (#424) (#430)

画面上でのテストは完了．
移行にす早さが求められるので，準備ができたらマージする．

Reviewed-on: #430
Co-authored-by: miteruzo <miteruzo@naver.com>

backend/spec/requests/materials_spec.rb

@@ -178,6 +178,7 @@ RSpec.describe 'Materials API', type: :request do
   end
 
   describe 'GET /materials/:id' do
+    include WikiRecords
     let!(:tag) do
       create(:tag, primary_name: 'material_show', category: :material)
     end
@@ -205,6 +206,56 @@ RSpec.describe 'Materials API', type: :request do
       get '/materials/999999999'
       expect(response).to have_http_status(:not_found)
     end
+
+    def get_material_without_legacy_reads
+      queries = []
+      subscriber = lambda do |*args|
+        sql = args.last.fetch(:sql)
+        if sql.match?(/\bSELECT\b/i) && sql.match?(/\bwiki_(pages|revisions|versions)\b/i)
+          queries << sql
+        end
+      end
+      ActiveSupport::Notifications.subscribed(subscriber, 'sql.active_record') do
+        get "/materials/#{ material.id }"
+      end
+      expect(response).to have_http_status(:ok)
+      expect(queries).to be_empty
+    end
+
+    it 'reads the description even when the legacy revision has different content' do
+      page = seed_wiki_page(tag_name: tag.tag_name('ja'), body: 'legacy body',
+                            created_by_user: member_user)
+      TagDescription.find_by!(tag_id: tag.id, language_code: 'ja')
+          .update!(body: 'description body')
+      get_material_without_legacy_reads
+      expect(json.fetch('wiki_page_body')).to eq('description body')
+      expect(page.current_revision.body).to eq('legacy body')
+    end
+
+    it 'uses tag_id rather than description ID without a Wiki page or TagName' do
+      description = TagDescription.create!(id: tag.id + 1000, tag:, language_code: 'ja',
+                                           body: 'independent body', version_no: 1)
+      tag.tag_names.update_all(tag_id: nil)
+      get_material_without_legacy_reads
+      expect(description.id).not_to eq(tag.id)
+      expect(json.fetch('wiki_page_body')).to eq('independent body')
+      expect(json.fetch('tag').fetch('has_wiki')).to be(true)
+    end
+
+    it 'returns nil when only legacy Wiki content exists' do
+      seed_wiki_page(tag_name: tag.tag_name('ja'), body: 'legacy only',
+                     created_by_user: member_user)
+      TagDescription.where(tag_id: tag.id).delete_all
+      get_material_without_legacy_reads
+      expect(json.fetch('wiki_page_body')).to be_nil
+      expect(json.fetch('tag').fetch('has_wiki')).to be(false)
+    end
+
+    it 'returns nil for an untagged material' do
+      material.update!(tag: nil)
+      get_material_without_legacy_reads
+      expect(json.fetch('wiki_page_body')).to be_nil
+    end
   end
 
   describe 'POST /materials' do