diff --git a/.rspec b/.rspec
new file mode 100644
index 00000000..c99d2e73
--- /dev/null
+++ b/.rspec
@@ -0,0 +1 @@
+--require spec_helper
diff --git a/Gemfile b/Gemfile
index e20b1260..63579dc1 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,16 +7,20 @@ gem 'rails', '~> 5.2.3'
 gem 'pg', '>= 0.18', '< 2.0'
 gem 'puma', '~> 3.11'
 gem 'bootsnap', '>= 1.1.0', require: false
+gem 'activerecord-import'
 
 group :development, :test do
-  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
-  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
+  gem 'pry'
+  gem 'rspec-rails'
+  gem 'rspec-benchmark'
 end
 
 group :development do
   # Access an interactive console on exception pages or by calling 'console' anywhere in the code.
   gem 'web-console', '>= 3.3.0'
   gem 'listen', '>= 3.0.5', '< 3.2'
+  gem 'rack-mini-profiler'
+  gem 'bullet'
 end
 
 group :test do
diff --git a/Gemfile.lock b/Gemfile.lock
index fccf6f5f..323c0a91 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -33,6 +33,8 @@ GEM
       activemodel (= 5.2.3)
       activesupport (= 5.2.3)
       arel (>= 9.0)
+    activerecord-import (1.0.4)
+      activerecord (>= 3.2)
     activestorage (5.2.3)
       actionpack (= 5.2.3)
       activerecord (= 5.2.3)
@@ -43,13 +45,20 @@ GEM
       minitest (~> 5.1)
       tzinfo (~> 1.1)
     arel (9.0.0)
+    benchmark-malloc (0.1.0)
+    benchmark-perf (0.5.0)
+    benchmark-trend (0.3.0)
     bindex (0.6.0)
     bootsnap (1.4.2)
       msgpack (~> 1.0)
     builder (3.2.3)
-    byebug (11.0.1)
+    bullet (6.1.0)
+      activesupport (>= 3.0.0)
+      uniform_notifier (~> 1.11)
+    coderay (1.1.2)
     concurrent-ruby (1.1.5)
     crass (1.0.4)
+    diff-lcs (1.3)
     erubi (1.8.0)
     ffi (1.10.0)
     globalid (0.4.2)
@@ -77,8 +86,13 @@ GEM
     nokogiri (1.10.2)
       mini_portile2 (~> 2.4.0)
     pg (1.1.4)
+    pry (0.12.2)
+      coderay (~> 1.1.0)
+      method_source (~> 0.9.0)
     puma (3.12.1)
     rack (2.0.6)
+    rack-mini-profiler (1.1.6)
+      rack (>= 1.2.0)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
     rails (5.2.3)
@@ -109,6 +123,32 @@ GEM
     rb-fsevent (0.10.3)
     rb-inotify (0.10.0)
       ffi (~> 1.0)
+    rspec (3.9.0)
+      rspec-core (~> 3.9.0)
+      rspec-expectations (~> 3.9.0)
+      rspec-mocks (~> 3.9.0)
+    rspec-benchmark (0.5.1)
+      benchmark-malloc (~> 0.1.0)
+      benchmark-perf (~> 0.5.0)
+      benchmark-trend (~> 0.3.0)
+      rspec (>= 3.0.0, < 4.0.0)
+    rspec-core (3.9.1)
+      rspec-support (~> 3.9.1)
+    rspec-expectations (3.9.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.9.0)
+    rspec-mocks (3.9.1)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.9.0)
+    rspec-rails (3.9.0)
+      actionpack (>= 3.0)
+      activesupport (>= 3.0)
+      railties (>= 3.0)
+      rspec-core (~> 3.9.0)
+      rspec-expectations (~> 3.9.0)
+      rspec-mocks (~> 3.9.0)
+      rspec-support (~> 3.9.0)
+    rspec-support (3.9.2)
     ruby_dep (1.5.0)
     sprockets (3.7.2)
       concurrent-ruby (~> 1.0)
@@ -121,6 +161,7 @@ GEM
     thread_safe (0.3.6)
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
+    uniform_notifier (1.13.0)
     web-console (3.7.0)
       actionview (>= 5.0)
       activemodel (>= 5.0)
@@ -134,12 +175,17 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  activerecord-import
   bootsnap (>= 1.1.0)
-  byebug
+  bullet
   listen (>= 3.0.5, < 3.2)
   pg (>= 0.18, < 2.0)
+  pry
   puma (~> 3.11)
+  rack-mini-profiler
   rails (~> 5.2.3)
+  rspec-benchmark
+  rspec-rails
   tzinfo-data
   web-console (>= 3.3.0)
 
diff --git a/app/controllers/trips_controller.rb b/app/controllers/trips_controller.rb
index acb38be2..1431925c 100644
--- a/app/controllers/trips_controller.rb
+++ b/app/controllers/trips_controller.rb
@@ -2,6 +2,6 @@ class TripsController < ApplicationController
   def index
     @from = City.find_by_name!(params[:from])
     @to = City.find_by_name!(params[:to])
-    @trips = Trip.where(from: @from, to: @to).order(:start_time)
+    @trips = Trip.includes(bus: :services).where(from: @from, to: @to).order(:start_time)
   end
 end
diff --git a/app/models/buses_services.rb b/app/models/buses_services.rb
new file mode 100644
index 00000000..9f4bd614
--- /dev/null
+++ b/app/models/buses_services.rb
@@ -0,0 +1,4 @@
+class BusesServices < ApplicationRecord
+  belongs_to :bus
+  belongs_to :service
+end
diff --git a/app/views/trips/_delimiter.html.erb b/app/views/trips/_delimiter.html.erb
deleted file mode 100644
index 3f845ad0..00000000
--- a/app/views/trips/_delimiter.html.erb
+++ /dev/null
@@ -1 +0,0 @@
-====================================================
diff --git a/app/views/trips/_service.html.erb b/app/views/trips/_service.html.erb
deleted file mode 100644
index 178ea8c0..00000000
--- a/app/views/trips/_service.html.erb
+++ /dev/null
@@ -1 +0,0 @@
-<li><%= "#{service.name}" %></li>
diff --git a/app/views/trips/_services.html.erb b/app/views/trips/_services.html.erb
deleted file mode 100644
index 2de639fc..00000000
--- a/app/views/trips/_services.html.erb
+++ /dev/null
@@ -1,6 +0,0 @@
-<li>Сервисы в автобусе:</li>
-<ul>
-  <% services.each do |service| %>
-    <%= render "service", service: service %>
-  <% end %>
-</ul>
diff --git a/app/views/trips/_trip.html.erb b/app/views/trips/_trip.html.erb
deleted file mode 100644
index fa1de9aa..00000000
--- a/app/views/trips/_trip.html.erb
+++ /dev/null
@@ -1,5 +0,0 @@
-<li><%= "Отправление: #{trip.start_time}" %></li>
-<li><%= "Прибытие: #{(Time.parse(trip.start_time) + trip.duration_minutes.minutes).strftime('%H:%M')}" %></li>
-<li><%= "В пути: #{trip.duration_minutes / 60}ч. #{trip.duration_minutes % 60}мин." %></li>
-<li><%= "Цена: #{trip.price_cents / 100}р. #{trip.price_cents % 100}коп." %></li>
-<li><%= "Автобус: #{trip.bus.model} №#{trip.bus.number}" %></li>
diff --git a/app/views/trips/index.html.erb b/app/views/trips/index.html.erb
index a60bce41..781e1d0c 100644
--- a/app/views/trips/index.html.erb
+++ b/app/views/trips/index.html.erb
@@ -7,10 +7,19 @@
 
 <% @trips.each do |trip| %>
   <ul>
-    <%= render "trip", trip: trip %>
+    <li><%= "Отправление: #{trip.start_time}" %></li>
+    <li><%= "Прибытие: #{(Time.parse(trip.start_time) + trip.duration_minutes.minutes).strftime('%H:%M')}" %></li>
+    <li><%= "В пути: #{trip.duration_minutes / 60}ч. #{trip.duration_minutes % 60}мин." %></li>
+    <li><%= "Цена: #{trip.price_cents / 100}р. #{trip.price_cents % 100}коп." %></li>
+    <li><%= "Автобус: #{trip.bus.model} №#{trip.bus.number}" %></li>
     <% if trip.bus.services.present? %>
-      <%= render "services", services: trip.bus.services %>
+      <li>Сервисы в автобусе:</li>
+      <ul>
+        <% trip.bus.services.each do |service| %>
+          <li><%= "#{service.name}" %></li>
+        <% end %>
+      </ul>
     <% end %>
   </ul>
-  <%= render "delimiter" %>
+  <%= '====================================================' %>
 <% end %>
diff --git a/case-study.md b/case-study.md
new file mode 100644
index 00000000..6874a564
--- /dev/null
+++ b/case-study.md
@@ -0,0 +1,155 @@
+# Case-study оптимизации
+
+## Актуальная проблема
+Дано веб-приложение для поиска рейсовых междугородних автобусов. В нем есть две основные проблемы.
+1. Для наполнения базы данными по рейсам используется рейк-таска, которая импортрует информацию о маршрутах из
+json файла. Операция импорта на больших файлах занимает слишком много времени. Необходимо снизить время этой операции.
+2. Необходимо оптимизировать рендер страницы со списком маршрутов. Сейчас она загружается слишком долго.
+
+## Формирование метрики
+В обоих проблема ключевой метрикой является время работы. Для поставленых задач определим для себя такие цели:
+1. Загрузка файла со 100_000 рейсов (large.json) в пределах 1 минуты.
+2. Устранить освновные проблемы при рендере индекса рейсов, загруженных из `large.json`.
+
+## Гарантия корректности работы оптимизированной программы
+Перед тем, как дербанить программу, напишем простой тест, чтобы убедиться, что выдача ручки с индексом рейсов
+не изменилась.
+```
+describe 'reload json task' do
+  ...
+  it 'creates all instances' do
+    expect(City.count).to eq 2
+    expect(Service.count).to eq 2
+    expect(Bus.count).to eq 1
+    expect(Trip.count).to eq 10
+  end
+
+  it 'creates correct instances' do
+    bus_attrs.each do |k, v|
+      expect(Bus.first.attributes[k]).to eq v
+    end
+    expect((Service.pluck(:name) & service_names).size).to eq 2
+    expect((City.pluck(:name) & city_names).size).to eq 2
+    first_trip_attrs.each do |k, v|
+      expect(Trip.first.attributes[k]).to eq v
+    end
+  end
+end
+```
+
+# Проблема 1
+## Feedback loop
+Для эффективного фидбек лупа напишем бенчмарк тест импорта данных.
+```
+describe 'large data import' do
+  it 'works under 1 minute' do
+    expect do
+      `rake "reload_json[fixtures/large.json]"`
+    end.to perform_under(60).sec
+  end
+end
+```
+
+При первом прогоне он ожидаемо не проходит.
+
+## Вникаем в детали системы, чтобы найти главные точки роста
+### Итерация 1
+Посмотрим на код таски импорта. Почти вся работа происходит в итерации по трипам.
+Попробуем включить ActiveRecord логгер и записать вывод в файл.
+```ruby
+ActiveRecord::Base.logger = Logger.new(STDOUT)
+```
+
+```
+$ touch asdf
+$ bundle exec rake 'reload_json[fixtures/small.json]' > asdf
+```
+
+Посчитаем количество инсертов и селектов, которые делаются скриптом при импорте `small.json` (1000 трипов).
+```
+$ grep INSERT asdf | wc -l
+4265
+$ grep SELECT asdf | wc -l
+9239
+```
+
+Проделаем то же самое с файлом `medium.json` (10_000 трипов).
+```
+$ grep INSERT asdf | wc -l
+15705
+$ grep SELECT asdf | wc -l
+96639
+```
+
+Как видим, количество инсертов и селектов огромно, и растет вместе с количеством трипов. И хотя каждый
+запрос достаточно быстр, в основном это считаные миллисекунды, все же огромное количество запросов
+сильно замедляет импорт. Воспользуемся библиотечкой `activerecord-import`, чтобы драматически сократить
+количество обращений в базу.
+
+Activerecord-import умеет возвращать информацию о количестве инсертов - сразу спросим его, скольо инсертов он
+сделал на те же инпуты, что в примерах выше.
+```
+$ bundle exec rake 'reload_json[fixtures/small.json]'
+5
+$ bundle exec rake 'reload_json[fixtures/medium.json]'
+5
+```
+
+Чудно! количество инсертов не растет с инпутом.
+Наш тест на корректность зеленый, поэтому попробуем тест на время импорта большого файла.
+```
+$ bundle exec rspec spec/tasks/reload_json_performance_spec.rb
+.
+
+Finished in 34.96 seconds (files took 0.51447 seconds to load)
+  1 example, 0 failures
+```
+
+Отлично! Импорт проходит за 35 секунд. Если попробовать утилиту `time`, то она покажет еще более
+оптимистичный результат в 18 секунд:
+```
+$ time bundle exec rake 'reload_json[fixtures/large.json]'
+bundle exec rake 'reload_json[fixtures/large.json]'  17.34s user 0.24s system 94% cpu 18.621 total
+```
+
+Воспользуемся в таске полезной фичей гема и сразу добавим вывод варнингов если есть зафейленые инсерты:
+```
+fails = []
+...
+fails += Service.import(services).failed_instances
+fails += City.import(cities.to_a).failed_instances
+fails += Bus.import(buses.to_a).failed_instances
+...
+if fails.any?
+  puts "Failed instances: #{fails}"
+else
+  puts 'Everything is fine.'
+end
+```
+И перейдем ко второй проблеме.
+
+# Проблема 2
+## Feedback loop
+Поставим `rack-mini-profiler`, чтобы отслеживать время рендера. Первый результат - больше 6 секунд.
+
+## Вникаем в детали системы, чтобы найти главные точки роста
+Попробуем посмотреть детальные отчеты мини профайлера, а так же поставим `bullet` чтобы избежать лишних запросов.
+
+### Итерация 1
+Сразу же видим подсказки от буллета - добавим к трипам `includes(bus: :services)`
+Время пребывания в базе сразу сократилось с примерно полутора секунд до 60мс.
+Теперь основное время занимает рендеринг паршиалов.
+
+### Итерация 2
+Попробуем избавиться от них полностью, перенеся все их содержимое прямо в `index.html.erb`.
+Время рендера вьюх сократилось почти вдвое!
+```
+Completed 200 OK in 3959ms (Views: 3890.6ms | ActiveRecord: 52.4ms)
+```
+
+Улучшать рендеринг далее, без вмешательства в работу рендера в самой рельсе скорее всего не удастся,
+а улучшать время работы в базе на фоне времени вьюхи не имеет смысла, поэтому остановимся на таком результате.
+
+# Результаты
+1. Время импорта `large.json` сократилось до 19 секунд.
+2. Время рендера индекса для этих данных сократилось до 4 секунд.
diff --git a/config/environments/development.rb b/config/environments/development.rb
index 1311e3e4..948e5224 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -58,4 +58,10 @@
   # Use an evented file watcher to asynchronously detect changes in source code,
   # routes, locales, etc. This feature depends on the listen gem.
   config.file_watcher = ActiveSupport::EventedFileUpdateChecker
+
+  config.after_initialize do
+    Bullet.enable = true
+    Bullet.add_footer = true
+  end
 end
+
diff --git a/config/routes.rb b/config/routes.rb
index a2da6a7b..27feb596 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -1,5 +1,4 @@
 Rails.application.routes.draw do
-  # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
   get "/" => "statistics#index"
   get "автобусы/:from/:to" => "trips#index"
 end
diff --git a/lib/tasks/utils.rake b/lib/tasks/utils.rake
index 540fe871..18cb8277 100644
--- a/lib/tasks/utils.rake
+++ b/lib/tasks/utils.rake
@@ -1,6 +1,8 @@
 # Наивная загрузка данных из json-файла в БД
 # rake reload_json[fixtures/small.json]
 task :reload_json, [:file_name] => :environment do |_task, args|
+  # ActiveRecord::Base.logger = Logger.new(STDOUT)
+  fails = []
   json = JSON.parse(File.read(args.file_name))
 
   ActiveRecord::Base.transaction do
@@ -8,27 +10,52 @@ task :reload_json, [:file_name] => :environment do |_task, args|
     Bus.delete_all
     Service.delete_all
     Trip.delete_all
-    ActiveRecord::Base.connection.execute('delete from buses_services;')
+    BusesServices.delete_all
+
+    cities = Set.new
+    buses = Set.new
+    trips = Set.new
+    buses_services = Set.new
+
+    services = Service::SERVICES.map { |name| Service.new(name: name) }
 
     json.each do |trip|
-      from = City.find_or_create_by(name: trip['from'])
-      to = City.find_or_create_by(name: trip['to'])
-      services = []
+      cities << { name: trip['from'] }
+      cities << { name: trip['to'] }
+      buses << { number: trip['bus']['number'], model: trip['bus']['model'] }
+    end
+
+    fails += Service.import(services).failed_instances
+    fails += City.import(cities.to_a).failed_instances
+    fails += Bus.import(buses.to_a).failed_instances
+
+    city_id_by_name = City.all.map { |city| [city.name, city.id] }.to_h
+    bus_id_by_number = Bus.all.map { |bus| [bus.number, bus.id] }.to_h
+    service_id_by_name = Service.all.map { |ser| [ser.name, ser.id] }.to_h
+
+    json.each do |trip|
+      bus_id = bus_id_by_number[trip['bus']['number']]
       trip['bus']['services'].each do |service|
-        s = Service.find_or_create_by(name: service)
-        services << s
+        service_id = service_id_by_name[service]
+        buses_services << { bus_id: bus_id, service_id: service_id }
       end
-      bus = Bus.find_or_create_by(number: trip['bus']['number'])
-      bus.update(model: trip['bus']['model'], services: services)
 
-      Trip.create!(
-        from: from,
-        to: to,
-        bus: bus,
+      trips << {
+        from_id: city_id_by_name[trip['from']],
+        to_id: city_id_by_name[trip['to']],
+        bus_id: bus_id_by_number[trip['bus']['number']],
         start_time: trip['start_time'],
         duration_minutes: trip['duration_minutes'],
-        price_cents: trip['price_cents'],
-      )
+        price_cents: trip['price_cents']
+      }
+    end
+
+    fails += Trip.import(trips.to_a).failed_instances
+    fails += BusesServices.import(buses_services.to_a).failed_instances
+    if fails.any?
+      puts "Failed instances: #{fails}"
+    else
+      puts 'Everything is fine.'
     end
   end
 end
diff --git a/spec/rails_helper.rb b/spec/rails_helper.rb
new file mode 100644
index 00000000..2d561e85
--- /dev/null
+++ b/spec/rails_helper.rb
@@ -0,0 +1,63 @@
+# This file is copied to spec/ when you run 'rails generate rspec:install'
+require 'spec_helper'
+ENV['RAILS_ENV'] ||= 'test'
+
+require File.expand_path('../config/environment', __dir__)
+
+# Prevent database truncation if the environment is production
+abort("The Rails environment is running in production mode!") if Rails.env.production?
+require 'rspec/rails'
+# Add additional requires below this line. Rails is not loaded until this point!
+
+# Requires supporting ruby files with custom matchers and macros, etc, in
+# spec/support/ and its subdirectories. Files matching `spec/**/*_spec.rb` are
+# run as spec files by default. This means that files in spec/support that end
+# in _spec.rb will both be required and run as specs, causing the specs to be
+# run twice. It is recommended that you do not name files matching this glob to
+# end with _spec.rb. You can configure this pattern with the --pattern
+# option on the command line or in ~/.rspec, .rspec or `.rspec-local`.
+#
+# The following line is provided for convenience purposes. It has the downside
+# of increasing the boot-up time by auto-requiring all files in the support
+# directory. Alternatively, in the individual `*_spec.rb` files, manually
+# require only the support files necessary.
+#
+# Dir[Rails.root.join('spec', 'support', '**', '*.rb')].each { |f| require f }
+
+# Checks for pending migrations and applies them before tests are run.
+# If you are not using ActiveRecord, you can remove these lines.
+begin
+  ActiveRecord::Migration.maintain_test_schema!
+rescue ActiveRecord::PendingMigrationError => e
+  puts e.to_s.strip
+  exit 1
+end
+RSpec.configure do |config|
+  # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
+  config.fixture_path = "#{::Rails.root}/fixtures"
+
+  # If you're not using ActiveRecord, or you'd prefer not to run each of your
+  # examples within a transaction, remove the following line or assign false
+  # instead of true.
+  config.use_transactional_fixtures = true
+
+  # RSpec Rails can automatically mix in different behaviours to your tests
+  # based on their file location, for example enabling you to call `get` and
+  # `post` in specs under `spec/controllers`.
+  #
+  # You can disable this behaviour by removing the line below, and instead
+  # explicitly tag your specs with their type, e.g.:
+  #
+  #     RSpec.describe UsersController, :type => :controller do
+  #       # ...
+  #     end
+  #
+  # The different available types are documented in the features, such as in
+  # https://relishapp.com/rspec/rspec-rails/docs
+  config.infer_spec_type_from_file_location!
+
+  # Filter lines from Rails gems in backtraces.
+  config.filter_rails_from_backtrace!
+  # arbitrary gems may also be filtered via:
+  # config.filter_gems_from_backtrace("gem name")
+end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
new file mode 100644
index 00000000..ce33d66d
--- /dev/null
+++ b/spec/spec_helper.rb
@@ -0,0 +1,96 @@
+# This file was generated by the `rails generate rspec:install` command. Conventionally, all
+# specs live under a `spec` directory, which RSpec adds to the `$LOAD_PATH`.
+# The generated `.rspec` file contains `--require spec_helper` which will cause
+# this file to always be loaded, without a need to explicitly require it in any
+# files.
+#
+# Given that it is always loaded, you are encouraged to keep this file as
+# light-weight as possible. Requiring heavyweight dependencies from this file
+# will add to the boot time of your test suite on EVERY test run, even for an
+# individual file that may not need all of that loaded. Instead, consider making
+# a separate helper file that requires the additional dependencies and performs
+# the additional setup, and require it from the spec files that actually need
+# it.
+#
+# See http://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
+RSpec.configure do |config|
+  # rspec-expectations config goes here. You can use an alternate
+  # assertion/expectation library such as wrong or the stdlib/minitest
+  # assertions if you prefer.
+  config.expect_with :rspec do |expectations|
+    # This option will default to `true` in RSpec 4. It makes the `description`
+    # and `failure_message` of custom matchers include text for helper methods
+    # defined using `chain`, e.g.:
+    #     be_bigger_than(2).and_smaller_than(4).description
+    #     # => "be bigger than 2 and smaller than 4"
+    # ...rather than:
+    #     # => "be bigger than 2"
+    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
+  end
+
+  # rspec-mocks config goes here. You can use an alternate test double
+  # library (such as bogus or mocha) by changing the `mock_with` option here.
+  config.mock_with :rspec do |mocks|
+    # Prevents you from mocking or stubbing a method that does not exist on
+    # a real object. This is generally recommended, and will default to
+    # `true` in RSpec 4.
+    mocks.verify_partial_doubles = true
+  end
+
+  # This option will default to `:apply_to_host_groups` in RSpec 4 (and will
+  # have no way to turn it off -- the option exists only for backwards
+  # compatibility in RSpec 3). It causes shared context metadata to be
+  # inherited by the metadata hash of host groups and examples, rather than
+  # triggering implicit auto-inclusion in groups with matching metadata.
+  config.shared_context_metadata_behavior = :apply_to_host_groups
+
+# The settings below are suggested to provide a good initial experience
+# with RSpec, but feel free to customize to your heart's content.
+=begin
+  # This allows you to limit a spec run to individual examples or groups
+  # you care about by tagging them with `:focus` metadata. When nothing
+  # is tagged with `:focus`, all examples get run. RSpec also provides
+  # aliases for `it`, `describe`, and `context` that include `:focus`
+  # metadata: `fit`, `fdescribe` and `fcontext`, respectively.
+  config.filter_run_when_matching :focus
+
+  # Allows RSpec to persist some state between runs in order to support
+  # the `--only-failures` and `--next-failure` CLI options. We recommend
+  # you configure your source control system to ignore this file.
+  config.example_status_persistence_file_path = "spec/examples.txt"
+
+  # Limits the available syntax to the non-monkey patched syntax that is
+  # recommended. For more details, see:
+  #   - http://rspec.info/blog/2012/06/rspecs-new-expectation-syntax/
+  #   - http://www.teaisaweso.me/blog/2013/05/27/rspecs-new-message-expectation-syntax/
+  #   - http://rspec.info/blog/2014/05/notable-changes-in-rspec-3/#zero-monkey-patching-mode
+  config.disable_monkey_patching!
+
+  # Many RSpec users commonly either run the entire suite or an individual
+  # file, and it's useful to allow more verbose output when running an
+  # individual spec file.
+  if config.files_to_run.one?
+    # Use the documentation formatter for detailed output,
+    # unless a formatter has already been configured
+    # (e.g. via a command-line flag).
+    config.default_formatter = "doc"
+  end
+
+  # Print the 10 slowest examples and example groups at the
+  # end of the spec run, to help surface which specs are running
+  # particularly slow.
+  config.profile_examples = 10
+
+  # Run specs in random order to surface order dependencies. If you find an
+  # order dependency and want to debug it, you can fix the order by providing
+  # the seed, which is printed after each run.
+  #     --seed 1234
+  config.order = :random
+
+  # Seed global randomization in this process using the `--seed` CLI option.
+  # Setting this allows you to use `--seed` to deterministically reproduce
+  # test failures related to randomization by passing the same `--seed` value
+  # as the one that triggered the failure.
+  Kernel.srand config.seed
+=end
+end
diff --git a/spec/tasks/reload_json_performance_spec.rb b/spec/tasks/reload_json_performance_spec.rb
new file mode 100644
index 00000000..5be729bd
--- /dev/null
+++ b/spec/tasks/reload_json_performance_spec.rb
@@ -0,0 +1,14 @@
+require 'rails_helper'
+require 'rspec-benchmark'
+
+RSpec.configure do |config|
+  config.include RSpec::Benchmark::Matchers
+end
+
+describe 'large data import' do
+  it 'works under 1 minute' do
+    expect do
+      `rake "reload_json[fixtures/large.json]"`
+    end.to perform_under(60).sec
+  end
+end
diff --git a/spec/tasks/reload_json_spec.rb b/spec/tasks/reload_json_spec.rb
new file mode 100644
index 00000000..f5aa39c6
--- /dev/null
+++ b/spec/tasks/reload_json_spec.rb
@@ -0,0 +1,42 @@
+require 'rails_helper'
+
+describe 'reload json task' do
+  let(:bus_attrs) { {"id"=>1, "number"=>"123", "model"=>"Икарус"} }
+  let(:service_names) { ["Туалет", "WiFi"] }
+  let(:city_names) { ["Москва", "Самара"] }
+  let(:first_trip_attrs) do
+    {
+      "id"=>1,
+      "from_id"=>1,
+      "to_id"=>2,
+      "start_time"=>"11:00",
+      "duration_minutes"=>168,
+      "price_cents"=>474,
+      "bus_id"=>1,
+    }
+  end
+
+  before do
+    `rake db:setup`
+    `rake "reload_json[fixtures/example.json]"`
+  end
+
+  it 'creates all instances' do
+    expect(City.count).to eq 2
+    expect(Service.count).to eq 10
+    expect(Bus.count).to eq 1
+    expect(BusesServices.count).to eq 2
+    expect(Trip.count).to eq 10
+  end
+
+  it 'creates correct instances' do
+    bus_attrs.each do |k, v|
+      expect(Bus.first.attributes[k]).to eq v
+    end
+    expect((Service.pluck(:name) & service_names).size).to eq 2
+    expect((City.pluck(:name) & city_names).size).to eq 2
+    first_trip_attrs.each do |k, v|
+      expect(Trip.first.attributes[k]).to eq v
+    end
+  end
+end