diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c3bb75015..1aa7b39df 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -10,13 +10,13 @@ jobs:
   code-style:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v3
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: 3.1.0
       - name: Gems cache
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           path: ~/gems
           key: gems-3.0.0-${{ hashFiles('*.gemspec', 'Gemfile') }}-${{ github.sha }}
@@ -47,13 +47,13 @@ jobs:
           - ruby-head
           - jruby-9.3
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v3
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
       - name: Gems cache
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           path: ~/gems
           key: gems-${{ matrix.ruby }}-${{ hashFiles('*.gemspec', 'Gemfile') }}-${{ github.sha }}
diff --git a/.github/workflows/experimental.yml b/.github/workflows/experimental.yml
new file mode 100644
index 000000000..a442b78e0
--- /dev/null
+++ b/.github/workflows/experimental.yml
@@ -0,0 +1,36 @@
+name: Experimental
+
+on:
+  schedule:
+    - cron: "6 20 * * 6"
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby:
+          - truffleruby-head
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+      - name: Gems cache
+        uses: actions/cache@v3
+        with:
+          path: ~/gems
+          key: gems-${{ matrix.ruby }}-${{ hashFiles('*.gemspec', 'Gemfile') }}-${{ github.sha }}
+          restore-keys: |
+            gems-${{ matrix.ruby }}-${{ hashFiles('*.gemspec', 'Gemfile') }}-
+            gems-${{ matrix.ruby }}-
+      - name: Install dependencies
+        run: |
+          gem install bundler
+          bundle config path ~/gems
+          bundle install --jobs 4 --retry 3
+      - name: Run tests
+        run: bundle exec rake spec
diff --git a/spec/prawn_manual_spec.rb b/spec/prawn_manual_spec.rb
index 2bc19adce..b41d35a31 100644
--- a/spec/prawn_manual_spec.rb
+++ b/spec/prawn_manual_spec.rb
@@ -4,12 +4,11 @@
 require 'digest/sha2'
 
 MANUAL_HASH =
-  case RUBY_ENGINE
-  when 'ruby'
-    '2c0279e0bff2a9120494a52aa46216c1871902b5e66a3537bd4d3cbd66db0096b43b6e1ae0e4e189b561c4db9fa1afacb6c41f260e3aaf942faae2fee352d35b'
-  when 'jruby'
-    '51baf6440907e9e38d22f50deafa91572aec1174e621c044ae077cfe3d4361982a505dae5f013dd06f64f38cb9b3a38d5a3f8f0903849591774e298a3c91d39a'
-  end
+  {
+    'ruby' => '2c0279e0bff2a9120494a52aa46216c1871902b5e66a3537bd4d3cbd66db0096b43b6e1ae0e4e189b561c4db9fa1afacb6c41f260e3aaf942faae2fee352d35b',
+    'jruby' => '51baf6440907e9e38d22f50deafa91572aec1174e621c044ae077cfe3d4361982a505dae5f013dd06f64f38cb9b3a38d5a3f8f0903849591774e298a3c91d39a',
+    'truffleruby' => '9cab8cd0736f239058ce8dc4b2915fe014e1461d434de456d9fbf140c2b69553f39accbe9acb38b974efd1e7d3e5dfddf77e99e0bdba56f43a8746a0e5fcf37b'
+  }.freeze
 
 RSpec.describe Prawn do
   describe 'manual' do
@@ -27,7 +26,7 @@
 
       hash = Digest::SHA512.hexdigest(s)
 
-      expect(hash).to eq MANUAL_HASH
+      expect(hash).to eq MANUAL_HASH[RUBY_ENGINE]
     end
   end
 end