isolate fiddle test under RUBY_BOX mode

Author: katsyoshi

.github/workflows/main.yml

@@ -31,3 +31,5 @@ jobs:
       run: bundle exec rake steep:check
     - name: Run the default task
       run: bundle exec rake
+    - name: Run test using Ruby::Box
+      run: RUBY_BOX=1 bundle exec rake test

Rakefile

@@ -7,8 +7,13 @@ require "steep/cli"
 
 task default: %i[test]
 
+def supported_ruby_box? = RUBY_VERSION >= "4.0.0" && ENV["RUBY_BOX"] == "1" && defined?(Ruby::Box)
+
 Rake::TestTask.new do |t|
   t.test_files = FileList['test/**/*_test.rb']
+  if supported_ruby_box?
+    t.test_files = FileList['test/caotral/linker/fiddle_test.rb']
+  end
 end
 
 namespace :steep do

test/caotral/linker/fiddle_test.rb

@@ -0,0 +1,27 @@
+require_relative "../../test_suite"
+
+class Caotral::Linker::FiddleMethodTest < Test::Unit::TestCase
+  include TestProcessHelper
+  def setup
+    @generated = []
+    omit("Ruby::Box is not supported in this environment") unless supported_ruby_box?
+  end
+
+  def teardown
+    @generated.each do |file|
+      File.delete(file) if File.exist?(file)
+    end
+  end
+
+  def test_sample_call_add_method
+    @generated = ["libtmp.so", "libtmp.so.o"]
+    @file = "sample/C/add.c"
+    IO.popen(["gcc", "-fPIC", "-c", "-o", "libtmp.so.o", "%s" % @file]).close
+    linker = Caotral::Linker.link!(inputs: ["libtmp.so.o"], output: "libtmp.so", linker: "self", shared: true, executable: false)
+    box = Ruby::Box.new
+    box.require("./sample/fiddle_add.rb")
+    assert_equal(10, box::X.add(3, 7))
+  end
+
+  private def supported_ruby_box? = RUBY_VERSION >= "4.0.0" && ENV["RUBY_BOX"] == "1" && defined?(Ruby::Box)
+end