class RSpec::Rails::Matchers::BeValid

def failure_message
  message = "expected #{actual.inspect} to be valid"
  if actual.respond_to?(:errors)
    errors = if actual.errors.respond_to?(:full_messages)
               actual.errors.full_messages
             else
               actual.errors
             end
    message << ", but got errors: #{errors.map(&:to_s).join(', ')}"
  end
  message
end

def failure_message_when_negated
  "expected #{actual.inspect} not to be valid"
end

def initialize(*args)
  @args = args
end

def matches?(actual)
  @actual = actual
  actual.valid?(*@args)
end