module RSpec::Rails::Mocks::ActiveRecordInstanceMethods

def [](key)

Transforms the key to a method and calls it. 
def [](key)
  send(key)
end

def destroy

Stubs `persisted?` to return `false` and `id` to return `nil`. 
def destroy
  self.stub(:persisted?) { false }
  self.stub(:id) { nil }
end

def new_record?

Returns the opposite of `persisted?` 
def new_record?
  !persisted?
end