Port test_no_warn_sub_feature.rb to RSpec example

spec/bundler/bundled_gems_spec.rb

@@ -153,6 +153,26 @@ def my
     expect(err).to be_empty
   end
 
+  it "Don't show warning fiddle/import when bigdecimal on Gemfile" do
+    build_lib "fiddle", "1.0.0" do |s|
+      s.write "lib/fiddle.rb", "puts 'fiddle'"
+      s.write "lib/fiddle/import.rb", "puts 'fiddle/import'"
+    end
+
+    script <<-RUBY, env: { "BUNDLER_SPEC_GEM_REPO" => gem_repo1.to_s }
+      gemfile do
+        source "https://gem.repo1"
+        path "#{lib_path}" do
+          gem "fiddle"
+        end
+      end
+
+      require "fiddle/import"
+    RUBY
+
+    expect(err).to be_empty
+  end
+
   it "Don't show warning with net/smtp when net-smtp on Gemfile" do
     build_lib "net-smtp", "1.0.0" do |s|
       s.write "lib/net/smtp.rb", "puts 'net-smtp'"

tool/test_for_warn_bundled_gems/test.sh

@@ -12,10 +12,6 @@ echo "* Show warning with zeitwerk"
 ruby test_warn_zeitwerk.rb
 echo
 
-echo "* Don't show warning bigdecimal/util when bigdecimal on Gemfile"
-ruby test_no_warn_sub_feature.rb
-echo
-
 echo "* Show warning with bootsnap and some gem in Gemfile"
 ruby test_warn_bootsnap_and_gem.rb
 echo