diff --git a/tool/bundler/test_gems.rb b/tool/bundler/test_gems.rb
index 6de392132a6f70..b78f5464cc0c6d 100644
--- a/tool/bundler/test_gems.rb
+++ b/tool/bundler/test_gems.rb
@@ -5,10 +5,11 @@
 gem "rack", "2.0.8"
 gem "webrick", "1.7.0"
 gem "rack-test", "~> 1.1"
-gem "compact_index", "~> 0.13.0"
+gem "compact_index", "~> 0.15.0"
 gem "sinatra", "~> 2.0"
 # for Ruby 2.6. bundler/spec/install/gemfile/sources_spec.rb is failed with sinatra-2.0.8.1 and tilt-2.2.0.
 gem "tilt", "~> 2.0.11"
 gem "rake", "13.0.1"
 gem "builder", "~> 3.2"
 gem "rb_sys"
+gem "rubygems-generate_index", "~> 1.1"