I was confused by what the test does, and had to ask @codeinthehole to
explain. Hopefully made it's intention a bit clearer now.

I'd like to move away from django_dynamic_fixture, factory_boy is so
much nicer.

This required extending the UnicodeCSVWriter to be able to deal with
file-like objects as well. This is used to create downloadable CSV files
in memory.

TestCase.assertEquals (note the s at the end) has been deprecated.
The only failing tests remaining are CSV related, which is not
surprising.

Prior to this change, it was possible to select child products in the
product dashboard. A new function get_parent_products_queryset was
introduced, analogues to the existing get_related_products_queryset. It
is not based on the BrowsableManager as I can envision scenarios where
that is extended to respect status fields or such like, which we should
ignore when selecting a parent field. Otherwise it wouldn't be possible
to e.g. add a few hidden products with child products.

Two issues in tests with the G library were fixed as well, were
unintentionally child products were created. If the product field is
left unspecified, it seems to pick a product instead of leaving it as
None.

The clean method was raising a KeyError when the date fields were empty.

The validation on the stockrecord form needed to be removed to allow
group products to be created, which don't have stock records.

They now must have a title