diff --git a/tool/fetch-bundled_gems.rb b/tool/fetch-bundled_gems.rb
index 080f4b1d65..f50bda360a 100755
--- a/tool/fetch-bundled_gems.rb
+++ b/tool/fetch-bundled_gems.rb
@@ -6,7 +6,9 @@ BEGIN {
   color = Colorize.new
 
   if ARGV.first.start_with?("BUNDLED_GEMS=")
-    bundled_gems = ARGV.shift[13..-1].split(" ")
+    bundled_gems = ARGV.shift[13..-1]
+    sep = bundled_gems.include?(",") ? "," : " "
+    bundled_gems = bundled_gems.split(sep)
     bundled_gems = nil if bundled_gems.empty?
   end
 
diff --git a/tool/test-bundled-gems.rb b/tool/test-bundled-gems.rb
index 7ccf872f59..9aad4c3b63 100644
--- a/tool/test-bundled-gems.rb
+++ b/tool/test-bundled-gems.rb
@@ -11,6 +11,9 @@ github_actions = ENV["GITHUB_ACTIONS"] == "true"
 allowed_failures = ENV['TEST_BUNDLED_GEMS_ALLOW_FAILURES'] || ''
 allowed_failures = allowed_failures.split(',').reject(&:empty?)
 
+# make test-bundled-gems BUNDLED_GEMS=gem1,gem2,gem3
+bundled_gems = ARGV.first || ''
+
 colorize = Colorize.new
 rake = File.realpath("../../.bundle/bin/rake", __FILE__)
 gem_dir = File.realpath('../../gems', __FILE__)
@@ -21,7 +24,7 @@ failed = []
 File.foreach("#{gem_dir}/bundled_gems") do |line|
   next if /^\s*(?:#|$)/ =~ line
   gem = line.split.first
-  next unless ARGV.empty? or ARGV.any? {|pat| File.fnmatch?(pat, gem)}
+  next unless bundled_gems.delete_prefix("BUNDLED_GEMS=").split(",").include?(gem)
   next unless File.directory?("#{gem_dir}/src/#{gem}/test")
 
   test_command = "#{ruby} -C #{gem_dir}/src/#{gem} #{rake} test"