class Rack::Lint::InputWrapper

def gets(*args)

# or +nil+ on EOF.
# * +gets+ must be called without arguments and return a string, 
def gets(*args)
  assert("rack.input#gets called with arguments") { args.size == 0 }
  v = @input.gets
  assert("rack.input#gets didn't return a String") {
    v.nil? or v.kind_of? String
  }
  v
end