I don´t know if it is the intended behaviour but it feels a little weird to me

class Driver
has_and_belong_to_many :cars
end

class Car
has_and_belong_to_many :drivers
end

> car=Car.new
> car.drivers<< Driver.new
> c.drivers.one?
=> true # Ok
> c.drivers.count
=> 0 # ¿?¿?¿?

I think that if the method #one? tells me that there is one member, the method #count should tell me the same...