Gemfile:

group :test do  
  gem 'jnunemaker-matchy'
end

test_helper.rb:

class ActiveSupport::TestCase
  custom_matcher :match do |receiver, matcher, args|
    regex = args[0]
    matcher.positive_failure_message = "Expected #{receiver} to match #{regex}"
    matcher.negative_failure_message = "Expected #{receiver} not to match #{regex}"
    receiver.match(regex) != nil
  end
end

Your test:

current_path.should match(/\/admin\/companies\/.+/)