class Shoulda::Matchers::ActionMailer::HaveSentEmailMatcher

def regexp_or_string_match_in_array(an_array, a_regexp_or_string)
  case a_regexp_or_string
  when Regexp
    an_array.any? { |string| string =~ a_regexp_or_string }
  when String
    an_array.include?(a_regexp_or_string)
  end
end