Before each method hook

before_each.rb

require 'active_support/all'

module BeforeEach
  extend ActiveSupport::Concern

  module InstanceMethods
    def before_each
      raise NotImplementedError('Please define before_each method')
    end
  end

  module ClassMethods
    def method_added(method)
      method = method.to_s.gsub(/_with(out)?_before$/, '')
      with_method, without_method = "#{method}_with_before", "#{method}_without_before"
  
      return if method == 'before_each' or method_defined?(with_method)
  
      define_method(with_method) do |*args, &block|
        before_each
        send(without_method, *args, &block)
      end
      alias_method_chain(method, :before)
    end
  end
end

class Foo
  include BeforeEach
  
  def before_each
    puts 'bar'
  end
  
  def foo
    puts 'foo'
  end
end

puts Foo.new.foo
# => bar
#    foo