Force GC for Ruby BOM

I am working on a project where I will manage a bunch of objects created by an external dll. I now start with my Scope class, which implements a patter to store the memory of other "issue" objects. Therefore, I need to call the release method on every reference that the Scope object will maintain when the Scope object is destroyed. This is my code:

module ServiceBus

  class Scope
    def initialize
      @releaseables = []

      ObjectSpace.define_finalizer(self, self.class.finalize(@releaseables))
    end

    def self.finalize(releaseables)
      proc { releaseables.each { |obj| obj.release } }
    end

    def add_obj(obj)
      raise "#{self.class} only support releasbles objects" unless obj.respond_to?(:release)
      @releaseables << obj
    end
  end
end

      

        
        
        
      

    

and my spec:

subject(:subject) { ServiceBus::Scope.new }

context "obj respons_to release" do
  let(:obj) do
    obj = double("ReleaseableObject")
    allow(obj).to receive(:release)

    obj
  end

  it "success" do
    subject.add_obj obj
  end

  it "call invoke for all added objects" do
    other_obj = double("ReleaseableObject")
    allow(other_obj).to receive(:release)

    subject.add_obj obj
    subject.add_obj other_obj

    subject = nil
    GC.start

    expect(other_obj).to have_received(:release)
    expect(other_obj).to have_received(:release)
  end
end

      

        
        
        
      

    

This doesn't work because finalization is never done before waiting. How to force GC to destroy object object.

Thanks in advance!