Rails 4.2 Mailer Problem

Since we updated our application to Rails 4.2, our mailer tests seems to
fail (or not) randomly.

Simplified mailer code:

class ReservationMailer < ActionMailer::Base
default from: ‘[email protected]’,
bcc: ‘[email protected]

def reservation_received(reservation)
@reservation = reservation
@product = reservation.product

mail to: @reservation.email,
     from: '[email protected] <[email protected]>',
     subject: "Bestätigung Eingang Vormerkung für Produkt #{@

product.name}"
end
end

Simplified test code:

reservation = Reservation.new(email: '[email protected]', product:

product)

email = 

ReservationMailer.reservation_received(reservation).deliver_now

assert_equal 1, ActionMailer::Base.deliveries.size

There are some more mailers very similar to this mailer and the tests
seem
to fail randomly.

That means, sometimes just one of these tests fail, sometimes two and
somewhen nothing fails.

I couldn’t figure out any problem, but maybe you can help me out :slight_smile: