This commit changes the code in post notification endpoint to handle a
serialised template (ie a `dict`) rather than a database object.
This is the first step towards being able to cache the template and not
hit the database on every request.
There should be no functional changes here, it’s just refactoring.
There are some changes to the tests where the signature of functions
has changed.
Importing of the template schema has to be done at a function level,
otherwise Marshmallow gets weird.
This commit also copies the `JSONModel` class from the admin app, which
turns serialised data (a dict made from JSON) into an object on which
certain predefined properties are allowed.
This means we can still do the caching of serialised data, without
having to change too much of the code in the app, or make it ugly by
sprinkling dict lookups everywhere.
We’re not copying all of JSONModel from the admin app, just the bits we
need. We don’t need to compare or hash these objects, they’re just used
for lookups. And redefining `__getattribute__` scares Leo.
`Notification.template` changed from being a Template relationship
to TemplateHistory. When a relationship attribute is being assigned,
SQLAlchemy checks that the assigned value type matches the relationship
type. Since most tests at the moment create a notification using a
Template instance this check fails.
Rewriting the tests to use TemplateHistory objects would require
changes to the majority of tests. Instead, when creating a notification
objects we assign the foreign key attributes directly. This skips the
SQLAlchemy type check, but we still get the constraint check on the
foreign keys, so a matching TemplateHistory object needs to exist in
the database.
we now no longer create a job. At the end of the post there is no
action, as we don't have any tasks to queue immediately - if it's a
real notification it'll get picked up in the evening scheduled task.
If it's a test notification, we create it with an initial status of
sending so that we can be sure it'll never get picked up - and then we
trigger the update-letter-notifications-to-sent-to-dvla task to sent
the sent-at/by.
