diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index e6a299e..b9c7de9 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -6,7 +6,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest]
-        ruby: ["ruby-head", "3.4", "3.3", "3.2"]
+        ruby: ["ruby-head", "4.0", "3.4", "3.3", "3.2"]
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v6
diff --git a/Gemfile.lock b/Gemfile.lock
index 64cb800..84a06d3 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -12,7 +12,8 @@ GEM
     json (2.16.0)
     language_server-protocol (3.17.0.5)
     lint_roller (1.1.0)
-    minitest (5.25.5)
+    minitest (6.0.1)
+      prism (~> 1.5)
     parallel (1.27.0)
     parser (3.3.10.0)
       ast (~> 2.4.1)
@@ -73,7 +74,7 @@ GEM
       rubocop-performance (~> 1.25.0)
     unicode-display_width (3.2.0)
       unicode-emoji (~> 4.1)
-    unicode-emoji (4.1.0)
+    unicode-emoji (4.2.0)
     yard (0.9.37)
     yard-doctest (0.1.17)
       minitest