diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index e0b68e6..80545fb 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['2.7', '3.0', '3.1', '3.2', '3.3', '3.4']
+        ruby-version: ['2.7', '3.0', '3.1', '3.2', '3.3', '3.4', '4.0']
         gemfile:
           - rails_6_1
           - rails_7_0
@@ -27,6 +27,12 @@ jobs:
           - rails_8_0
           - rails_8_1
         exclude:
+          - ruby-version: '4.0'
+            gemfile: rails_6_1
+          - ruby-version: '4.0'
+            gemfile: rails_7_0
+          - ruby-version: '4.0'
+            gemfile: rails_7_1
           - ruby-version: '3.4'
             gemfile: rails_6_1
           - ruby-version: '3.4'
diff --git a/gemfiles/rails_6_1.gemfile b/gemfiles/rails_6_1.gemfile
index 87bd039..3fcd2a3 100644
--- a/gemfiles/rails_6_1.gemfile
+++ b/gemfiles/rails_6_1.gemfile
@@ -3,4 +3,6 @@ source "https://rubygems.org"
 gem "rails", "~> 6.1.0"
 gem "sqlite3", "~> 1.4"
 gem "concurrent-ruby", "< 1.3.5"
+gem "minitest", "< 6.0.0"
+
 gemspec path: '../'
diff --git a/gemfiles/rails_7_0.gemfile b/gemfiles/rails_7_0.gemfile
index 9ebf509..9b09e60 100644
--- a/gemfiles/rails_7_0.gemfile
+++ b/gemfiles/rails_7_0.gemfile
@@ -3,5 +3,6 @@ source "https://rubygems.org"
 gem "rails", "~> 7.0.0"
 gem "sqlite3", "~> 1.4"
 gem "concurrent-ruby", "< 1.3.5"
+gem "minitest", "< 6.0.0"
 
 gemspec path: '../'
diff --git a/gemfiles/rails_7_1.gemfile b/gemfiles/rails_7_1.gemfile
index 291eedd..17661ef 100644
--- a/gemfiles/rails_7_1.gemfile
+++ b/gemfiles/rails_7_1.gemfile
@@ -3,5 +3,6 @@ source "https://rubygems.org"
 gem "rails", "~> 7.1.0"
 gem "sqlite3", "~> 1.4"
 gem "logger", ">= 1.6.0"
+gem "minitest", "< 6.0.0"
 
 gemspec path: '../'
diff --git a/gemfiles/rails_7_2.gemfile b/gemfiles/rails_7_2.gemfile
index e7fdb45..fc5839b 100644
--- a/gemfiles/rails_7_2.gemfile
+++ b/gemfiles/rails_7_2.gemfile
@@ -3,5 +3,6 @@ source "https://rubygems.org"
 gem "rails", "~> 7.2.0"
 gem "sqlite3"
 gem "logger", ">= 1.6.0"
+gem "minitest", "< 6.0.0"
 
 gemspec path: '../'
diff --git a/gemfiles/rails_8_0.gemfile b/gemfiles/rails_8_0.gemfile
index 427b468..b97d551 100644
--- a/gemfiles/rails_8_0.gemfile
+++ b/gemfiles/rails_8_0.gemfile
@@ -3,5 +3,6 @@ source "https://rubygems.org"
 gem "rails", "~> 8.0.0"
 gem "sqlite3"
 gem "logger", ">= 1.6.0"
+gem "minitest", "< 6.0.0"
 
 gemspec path: '../'
diff --git a/gemfiles/rails_8_1.gemfile b/gemfiles/rails_8_1.gemfile
index 787c886..591d391 100644
--- a/gemfiles/rails_8_1.gemfile
+++ b/gemfiles/rails_8_1.gemfile
@@ -3,5 +3,6 @@ source "https://rubygems.org"
 gem "rails", "~> 8.1.0"
 gem "sqlite3"
 gem "logger", ">= 1.6.0"
+gem "minitest", "< 6.0.0"
 
 gemspec path: '../'