Fixes #2547.

Also fix the max_length on the url field. The underlying model field has
a max_length of 100, so it is invalid to have a larger value here.

DRY out dashboard page update/create views.

Refactor tests - perform tests of form logic directly rather than indirectly through view code.

Fixes #2559.

The priority isn't strictly a "restriction", but this seems like the most sensible form to add it to.

Notification subjects have a max length of 255 characters, which can easily be exceeded by long product names. Change the alert logic to provide a short notification subject and put the longer content in the notification body.

This patch also modifies the notification utils to make it obvious that the positional argument is a notification subject, not a body.

This is to prevent the possibility of spamming a user by generating lots of alert confirmation emails for product alerts.

Also allow unconfirmed alerts to be cancelled - we send a cancellation link in the confirmation email, so we should let users cancel an alert if they don't want to confirm it.

Fixes #2401.

Better to use filenames which are commonly used in the python word then
custom ones.

Latter one is deprecated

A dict_values object was returned instead of a list. See #2223

Future tasks is to dig into self.assertRedirectsTo wouldn't work with the test
as it stands

This provides a minimal login template to access the dashboard. This is
especially useful when the shop doesn't provide accounts.

See #1474

These tests will fail without this PR fix.

Replace 'assert' with 'assert*' method.

Convert tests.unit.forms.widget_tests to use TestCase class.

Convert bankcard tests to use TestCase.

Convert tests.unit.logging_tests to use TestCase.

Create a factory module per app and move them under the new
oscar.test.factories module.

The test belongs to the other functional dashboard order tests

This also removes the attr() marking of tests. This can be implemented
in pytest with marking the tests with a custom marker if required.

The `create_test_category_tree` doesn’t assert anything and is already tested via the integration tests.

Adds new functional tests for ShippingAddressView, PaymentDetailsView
and ThankYouView.
It's the second part of #1645.

Notes

* Adds a custom template to be able to test some functionalities of
  PaymentDetailsView
* Adds an helper to the CheckoutMixin

That approach is around from sometime around Oscar 0.6. With the
category refactor, it has become expensive to support. I doubt it has
any SEO impact, as e.g. Amazon has product IDs etc. all over their URLs.
@mbertheau seconded this opinion.

When we stopped storing the concatenated slugs on each category,
generating the URL for an individual category got more expensive. But
luckily it is safe to naively cache it, as the matching view only
considers the primary key any way. So even a stale cache should lead to
the right category.