diff --git a/stimulus_reflex.gemspec b/stimulus_reflex.gemspec
index d2662980..bfdede88 100644
--- a/stimulus_reflex.gemspec
+++ b/stimulus_reflex.gemspec
@@ -58,4 +58,5 @@ Gem::Specification.new do |gem|
   gem.add_development_dependency "rails", *rails_version
   gem.add_development_dependency "rake", "~> 13.0"
   gem.add_development_dependency "standard", "~> 1.24"
+  gem.add_development_dependency "minitest", "5.18.1"
 end