This makes sure out fixture data for node tests
is realistic, according to the schemas in
zerver/lib/event_schema.py.
Note that we are still in the process of extracting
schemas from test_events.py -> event_schema.py,
so the checks here are somewhat incomplete as of
now.
One nice thing is that the program will tell us
what checkers are missing, so this can motivate
us to move more checkers to event_schema.py.
I considered just making this happen as part of
tools/test-js-with-node, but it's convenient to
run by itself. Also, it currently requires
Django (although we could fix that), which makes
it just expensive enough that I wouldn't want
to always run it before the node tests.
Steve Howell