random.seed question (not reproducing same sequence)

[Nick Mellor]

Thanks John and others,

Replies much appreciated. I don't know how it could affect the results, but the function being tested is using redis. And I am running the test code under PyCharm, so perhaps using the module-level random number generator wasn't such a good idea. Live and learn.

In response to your question, John, all I know is that my own code doesn't use the random module outside of this code fragment.

Ned, thanks for the tip about creating a new instance of Random(). The test failures are still happening when the stockbins are randomised (as in code below.) That is suggesting that my code is somehow at fault.

Peter, I am using PyCharm as I said. But using a new Random() object to generate the sequence doesn't solve the problem apparently. The code now looks like this:

            rnd = random.Random()
            ...
            for qty in [4, 0]:
                rnd.seed(seed)
                for cart in range(test_size):
                    for special in range(rnd.randrange(3)):
                        s.addUpdate_special_to_cart(cart=cart, stockbin=rnd.randrange(test_size),
                                                    special_id=rnd.randrange(test_size), special_qty=qty,
                                                    products=[(rnd.choice(PRODUCTS), rnd.choice(range(10)))
                                                              for r in range(rnd.randrange(7))])


Cheers,

Nick