# File lib/test/rails/controller_test_case.rb, line 273
  def assert_flash(key, content)
    assert flash.include?(key),
           "#{key.inspect} missing from flash, has #{flash.keys.inspect}"

    case content
    when Regexp then
      assert_match content, flash[key],
                   "Content of flash[#{key.inspect}] did not match"
    else
      assert_equal content, flash[key],
                   "Incorrect content in flash[#{key.inspect}]"
    end
  end