[PEAK] model unit tests and a non-association QueryLink

[R. David Murray]

My unit testing is going pretty well.  I built a test harness for
my model tests that worked fine for most of the classes.  Now,
however, I'm trying to deal with a field that in my real storage
implementation is a QueryLink, but is not an association in the
model.

Here's what I've tried:

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class Harness(binding.Component):

    class dummyDM(storage.EntityDM):
        def _new(self, ob):
            if not hasattr(ob, id):
                self.lastid = getattr(self, 'lastid', 0) + 1
                ob.id = str(self.lastid)
            self._save(ob)
            return ob.id
        def _save(self, ob):
            self.data[ob.id] = ob
        def _load(self, id, ob):
            return self.data[id].__dict__

    class unbilledTransactionsForBilledAccount(storage.QueryDM):
        Transactions = binding.Obtain(storage.DMFor(Transaction))
        def _load(self, oid, ob):
            print "unbilled called"
            return [ x for x in Transactions.data if x.billedaccount.id == oid
                and not x.billedon ]

    class AccountDM(dummyDM):
        unbilled = binding.Obtain(PropertyName('test.unbilled'))
        def _new(self, ob):
            ob.unbilledtransactions = storage.QueryLink(self.unbilled[ob.id])
            super(Harness.AccountDM,self)._new(ob)

    Account = binding.Make(AccountDM, offerAs=[storage.DMFor(Account)])
    unbilled = binding.Make(unbilledTransactionsForBilledAccount,
        offerAs=[PropertyName('test.unbilled')])
    for m in (g for g in models if g!='Account'):
        exec("%s = binding.Make(dummyDM, offerAs=[storage.DMFor(%s)])" % (m, m))
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However, when I run my tests that print statement in unbilled never gets run,
and the unbilledtransactions attribute always has the value [].

I'm sure it is something simple I'm overlooking (like maybe I can't set
an attribute to a QueryLink directly?), and there may well be easier
ways to do this or I may be doing other things wrong in this harness.
So any comments are welcome.

Hmm.  Maybe my storage model is flawed?  I mean, how can a QueryLink
know that it needs to invaliate its value when the database rows
it is based on change, when it isn't being updated by an association?

In case it helps, the model is that a transaction has a 'billedon'
of None until it is added to a bill, at which time its billedon
becomes the bill it was assigned to.  So an account's unbilledtransactions
are all those transactions for which it is the billed account but
where the transaction hasn't yet been assigned to a bill.

--David