diff --git a/Gemfile b/Gemfile
index 62433c8..168ee39 100644
--- a/Gemfile
+++ b/Gemfile
@@ -47,4 +47,5 @@ gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
 
 group :test do
   gem 'rspec-rails'
+  gem 'deep-cover'
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index 21add46..a59d38b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -56,18 +56,37 @@ GEM
       minitest (~> 5.1)
       tzinfo (~> 1.1)
       zeitwerk (~> 2.2)
+    ast (2.4.0)
+    backports (3.17.1)
     bindex (0.8.1)
+    binding_of_caller (0.8.0)
+      debug_inspector (>= 0.0.1)
     bootsnap (1.4.6)
       msgpack (~> 1.0)
     builder (3.2.4)
     byebug (11.1.3)
+    coderay (1.1.2)
     concurrent-ruby (1.1.6)
     crass (1.0.6)
+    debug_inspector (0.0.3)
+    deep-cover (0.8.0)
+      deep-cover-core (= 0.8.0)
+      highline
+      thor (>= 0.20.3)
+      with_progress
+    deep-cover-core (0.8.0)
+      backports (>= 3.11.0)
+      binding_of_caller
+      parser (>= 2.5)
+      pry
+      term-ansicolor
+      terminal-table
     diff-lcs (1.3)
     erubi (1.9.0)
     ffi (1.12.2)
     globalid (0.4.2)
       activesupport (>= 4.2.0)
+    highline (2.0.3)
     i18n (1.8.2)
       concurrent-ruby (~> 1.0)
     jbuilder (2.10.0)
@@ -92,6 +111,11 @@ GEM
     nio4r (2.5.2)
     nokogiri (1.10.9)
       mini_portile2 (~> 2.4.0)
+    parser (2.7.1.2)
+      ast (~> 2.4.0)
+    pry (0.13.1)
+      coderay (~> 1.1)
+      method_source (~> 1.0)
     puma (4.3.3)
       nio4r (~> 2.0)
     rack (2.2.2)
@@ -146,6 +170,7 @@ GEM
       rspec-mocks (~> 3.9)
       rspec-support (~> 3.9)
     rspec-support (3.9.2)
+    ruby-progressbar (1.10.1)
     ruby_dep (1.5.0)
     sass-rails (6.0.0)
       sassc-rails (~> 2.1, >= 2.1.1)
@@ -169,14 +194,22 @@ GEM
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)
     sqlite3 (1.4.2)
+    sync (0.5.0)
+    term-ansicolor (1.7.1)
+      tins (~> 1.0)
+    terminal-table (1.8.0)
+      unicode-display_width (~> 1.1, >= 1.1.1)
     thor (1.0.1)
     thread_safe (0.3.6)
     tilt (2.0.10)
+    tins (1.24.1)
+      sync
     turbolinks (5.2.1)
       turbolinks-source (~> 5.2)
     turbolinks-source (5.2.0)
     tzinfo (1.2.7)
       thread_safe (~> 0.1)
+    unicode-display_width (1.7.0)
     web-console (4.0.1)
       actionview (>= 6.0.0)
       activemodel (>= 6.0.0)
@@ -189,6 +222,8 @@ GEM
     websocket-driver (0.7.1)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.4)
+    with_progress (1.0.1)
+      ruby-progressbar (~> 1.4)
     zeitwerk (2.3.0)
 
 PLATFORMS
@@ -197,6 +232,7 @@ PLATFORMS
 DEPENDENCIES
   bootsnap (>= 1.4.2)
   byebug
+  deep-cover
   jbuilder (~> 2.7)
   listen (>= 3.0.5, < 3.2)
   puma (~> 4.1)
diff --git a/spec/rails_helper.rb b/spec/rails_helper.rb
index 00345af..fdfc714 100644
--- a/spec/rails_helper.rb
+++ b/spec/rails_helper.rb
@@ -1,4 +1,4 @@
-# This file is copied to spec/ when you run 'rails generate rspec:install'
+require 'deep-cover'
 require 'spec_helper'
 ENV['RAILS_ENV'] ||= 'test'
 require File.expand_path('../config/environment', __dir__)