Overriding the constructor

1_record_finder.rb

class RecordFinder
  def initialize username, password
    @username = username
    @password = password
  end
end

2_my_override.rb

RecordFinder.class_eval do
  def initialize
    @username = ENV['USERNAME']
    @password = ENV['PASSWORD']
  end
end

# now, in my code, I can type:
#
# RecordFinder.new
# 
# and in my tests, I can stub it like:
#
# RecordFinder.stubs(:new).returns record_finder
# instead of...
# RecordFinder.stubs(:new).with(username, password).returns record_finder