Beau's tumblr

A possibly dangerous habit I’ve taken up lately is using Delegate in ruby as a way of changing the behaviour of a nasty dependency that’s just too prevalent in the system to break.

(The possibly dangerous part is that I’m still leaving dependencies hanging around that I know should be broken now, but oh well.)

Noticed something today that took me a long time to track down: methods that have been overridden by the delegating class, can’t be stubbed simply with instance.stub!(:method), as the stub! method gets proxied to the underlying delegate and the overriding method in the delegator is left as is.

Update: The code I ended up using instead of a Delegate in this case

module ConnectionProxies
  class ConnectionProxy
    def initialize(obj)
      @connection = obj
    end

    #proxy all of these methods straight to the underlying connection
    [
      :create_table,
      :transaction,
      :quote,
      :execute,
      :native_database_types,
      :adapter_name,
      :table_exists?,
      :columns
    ].each do |method|
      define_method(method) do |*args,&block|
        @connection.send(method,*args,&block)
      end
    end

  end
end