Fixed. NPlusOneQuery duplicate offense

spec/rubocop/cop/isucon/mysql2/n_plus_one_query_spec.rb

@@ -25,6 +25,35 @@
         end
       end
 
+      context "with single line SQL (2)" do
+        it "registers an offense" do
+          # c.f. https://github.com/isucon/isucon11-final/blob/667be3ec70c025eadde541e21d5ab1167efa1dd3/webapp/ruby/app.rb#L171-L190
+          expect_offense(<<~RUBY)
+            courses = db.xquery(
+              "SELECT `courses`.*" \\
+              " FROM `courses`" \\
+              " JOIN `registrations` ON `courses`.`id` = `registrations`.`course_id`" \\
+              " WHERE `courses`.`status` != ? AND `registrations`.`user_id` = ?",
+              STATUS_CLOSED, user_id,
+            )
+    
+            courses.map do |course|
+              teacher = db.xquery('SELECT * FROM `users` WHERE `id` = ?', course[:teacher_id]).first
+                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This looks like N+1 query.
+              raise unless teacher
+    
+              {
+                id: course[:id],
+                name: course[:name],
+                teacher: teacher[:name],
+                period: course[:period],
+                day_of_week: course[:day_of_week],
+              }
+            end
+          RUBY
+        end
+      end
+
       context "with multiple line SQL" do
         it "registers an offense" do
           expect_offense(<<~RUBY)