diff --git a/.rubocop.yml b/.rubocop.yml
index 6dcd847..c4d4d5d 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,3 +1,7 @@
+require:
+  - rubocop-rake
+  - rubocop-rspec
+
 AllCops:
   TargetRubyVersion: 3.0
   NewCops: enable
diff --git a/Gemfile b/Gemfile
index eabfc3d..ecf170e 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,6 +7,12 @@ gemspec
 
 group :development, :test do
   gem 'rake', '~> 13.0'
-  gem 'rspec', '~> 3.0'
-  gem 'rubocop', '~> 1.21'
+  gem 'rubocop', require: false
+  gem 'rubocop-rake', require: false
+  gem 'rubocop-rspec', require: false
+end
+
+group :test do
+  gem 'rspec', require: false
+  gem 'simplecov', require: false
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index 9deb691..514e799 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -8,6 +8,7 @@ GEM
   specs:
     ast (2.4.2)
     diff-lcs (1.5.1)
+    docile (1.4.1)
     json (2.7.2)
     language_server-protocol (3.17.0.3)
     parallel (1.26.3)
@@ -43,7 +44,17 @@ GEM
       unicode-display_width (>= 2.4.0, < 3.0)
     rubocop-ast (1.32.3)
       parser (>= 3.3.1.0)
+    rubocop-rake (0.6.0)
+      rubocop (~> 1.0)
+    rubocop-rspec (3.1.0)
+      rubocop (~> 1.61)
     ruby-progressbar (1.13.0)
+    simplecov (0.22.0)
+      docile (~> 1.1)
+      simplecov-html (~> 0.11)
+      simplecov_json_formatter (~> 0.1)
+    simplecov-html (0.13.1)
+    simplecov_json_formatter (0.1.4)
     unicode-display_width (2.6.0)
 
 PLATFORMS
@@ -52,9 +63,12 @@ PLATFORMS
 
 DEPENDENCIES
   rake (~> 13.0)
-  rspec (~> 3.0)
-  rubocop (~> 1.21)
+  rspec
+  rubocop
+  rubocop-rake
+  rubocop-rspec
   sheet_zoukas!
+  simplecov
 
 BUNDLED WITH
    2.5.16
diff --git a/spec/sheet_zoukas_spec.rb b/spec/sheet_zoukas_spec.rb
index 4c7f75f..c837e1b 100644
--- a/spec/sheet_zoukas_spec.rb
+++ b/spec/sheet_zoukas_spec.rb
@@ -2,7 +2,7 @@
 
 RSpec.describe SheetZoukas do
   it 'has a version number' do
-    expect(SheetZoukas::VERSION).not_to be nil
+    expect(SheetZoukas::VERSION).not_to be_nil
   end
 
   # it 'does something useful' do
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 08fa36c..5256c05 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,6 +1,11 @@
 # frozen_string_literal: true
 
 require 'sheet_zoukas'
+require 'simplecov'
+
+SimpleCov.start do
+  enable_coverage :branch
+end
 
 RSpec.configure do |config|
   # Enable flags like --only-failures and --next-failure