diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e7ca754..5fc1db7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby-version: ['3.1.7', '3.2.7', '3.3.7', '3.4.3']
+        ruby-version: ['3.1', '3.2', '3.3', '3.4', 'head']
 
     steps:
     - uses: actions/checkout@v4
@@ -39,7 +39,7 @@ jobs:
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: '3.4.2'
+        ruby-version: 'head'
         bundler-cache: true
 
     - name: Check code formatting
diff --git a/Gemfile b/Gemfile
index 40b5c9c..b9e716b 100644
--- a/Gemfile
+++ b/Gemfile
@@ -10,6 +10,7 @@ group :development do
 end
 
 group :test do
+  gem "benchmark"
   gem "csv"
   gem "rspec"
   gem "rubocop"