class Molinillo::Resolver::Resolution

def locked_requirement_possibility_set(requirement, activated = self.activated)
  all_possibilities = search_for(requirement)
  locked_requirement = locked_requirement_named(name_for(requirement))
  # Longwinded way to build a possibilities array with either the locked
  # requirement or nothing in it. Required, since the API for
  # locked_requirement isn't guaranteed.
  locked_possibilities = all_possibilities.select do |possibility|
    requirement_satisfied_by?(locked_requirement, activated, possibility)
  end
  group_possibilities(locked_possibilities)
end