Install RBS only if RUBY_VERSION => “3.0.0”

Author: soutaro

Gemfile

@@ -2,5 +2,7 @@ source "https://rubygems.org"
 
 gemspec
 
-gem "rbs", "~> 3.4"
-gem "rdoc"
+if RUBY_VERSION >= "3.0.0"
+  gem "rbs", "~> 3.4"
+  gem "rdoc"
+end

test/test_rbs_types.rb

@@ -1,6 +1,10 @@
 require 'test/unit'
 require 'mutex_m'
-require 'rbs/unit_test'
+begin
+  require 'rbs/unit_test'
+rescue LoadError
+  return
+end
 
 module RBSTypeTest
   class Mutex_mInstanceTest < Test::Unit::TestCase