module RuboCop::Cop::RSpec::ExplicitHelper

def to_predicate_method(matcher)
  case matcher = matcher.to_s
  when 'be_a', 'be_an', 'be_a_kind_of', 'a_kind_of', 'be_kind_of'
    'is_a?'
  when 'be_an_instance_of', 'be_instance_of', 'an_instance_of'
    'instance_of?'
  when 'include'
    'include?'
  when 'respond_to'
    'respond_to?'
  when /\Ahave_(.+)/
    "has_#{Regexp.last_match(1)}?"
  else
    "#{matcher[/\Abe_(.+)/, 1]}?"
  end
end