Unset Ruby constant

helper.rb

      ##
      # Unsets constant `const_name` from all available Modules.
      # Will not do anything, if constant not constantizable.
      #
      # Params:
      #   - const_name {Symbol} or {String} name of constant,
      #                able to be constantized
      #
      # Returns {Boolean} as a result of unsetting
      def unset_const!(const_name)
        return false unless const_name.to_s.safe_constantize

        const_name = const_name.to_sym
        const_owners = Module.constants.select do |c|
          c.to_s.constantize.
            constants(false).include?(const_name) rescue false
        end

        const_owners.each do |owner|
          puts "#{owner} defines #{const_name}, unsetting."
          owner.to_s.constantize.send(:remove_const, const_name)
        end
        true
      end

helper_spec.rb

  describe 'unsets any constant from all owners' do
    before do
      module Rails; end
    end

    it 'returns if constant not present' do
      subject.unset_const!(:FooBar).should be_false
    end

    context 'with single owner' do
      it "by finding it's owner" do
        subject.unset_const!(:Rails)
        defined?(Rails).should_not eq 'constant'
      end

    end
    context 'with multiple owners' do
      before do
        module Dummy
          module Rails; end
        end
      end

      it "by finding it's multiple owners" do
        subject.unset_const!('Rails')
        defined?(Rails).should_not eq 'constant'
      end

      after do
        Dummy.send(:remove_const, :Rails)  if defined?(::Dummy::Rails)
        Object.send(:remove_const, :Dummy) if defined?(::Dummy)
      end
    end

    after do
      Object.send(:remove_const, :Rails) if defined?(::Rails)
    end
  end