module T::AbstractUtils

def self.abstract_methods_for(mod)

that have not been implemented.
Given a module, returns the set of methods declared as abstract (in itself or ancestors) 
def self.abstract_methods_for(mod)
  declared_methods = declared_abstract_methods_for(mod)
  declared_methods.select do |declared_method|
    actual_method = mod.instance_method(declared_method.name)
    # Note that in the case where an abstract method is overridden by another abstract method,
    # this method will return them both. This is intentional to ensure we validate the final
    # implementation against all declarations of an abstract method (they might not all have the
    # same signature).
    abstract_method?(actual_method)
  end
end