require 'rails_helper' describe LiquidDroppable do before do class DroppableTest include LiquidDroppable def initialize(value) @value = value end attr_reader :value def to_s "[value:#{value}]" end end class DroppableTestDrop def value @object.value end end end describe 'test class' do it 'should be droppable' do five = DroppableTest.new(5) expect(five.to_liquid.class).to eq(DroppableTestDrop) expect(Liquid::Template.parse('{{ x.value | plus:3 }}').render('x' => five)).to eq('8') expect(Liquid::Template.parse('{{ x }}').render('x' => five)).to eq('[value:5]') end end end