Using Django Q filters with mocked instances, doesn't work as expected!

[mehdi-essebbar]

THE METHOD BEING TESTED:

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from repo.models import Expert
from django.db.models import Q

def method_to_test():
experts = Expert.objects.filter(Q(firstname__iregex='^a.*'))
return experts

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THE TEST IMPLEMENTATION:

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def test_q_expr(experts):
@mocked_relations(Expert)
def mocking_instances(qs):

    for exp in experts:
        m = MockModel(firstname='a' + exp.firstname, user=exp.user)
        Expert.objects.add(m)

    vals = method_to_test()
    print(len(vals))
    return vals

results = mocking_instances()
print(len(results))
assert False

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THE ERROR OUTPUT:

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==================================== FAILURES ====================================
__________________________________ test_q_expr ___________________________________

experts = [<Expert: Zmzhn 70214>, <Expert: Tt2vj JBL94>, <Expert: F4vm7 JU0H6>]

def test_q_expr(experts):
    @mocked_relations(Expert)
    def mocking_instances(qs):

        for exp in experts:
            m = MockModel(firstname='a' + exp.firstname, user=exp.user)
            Expert.objects.add(m)

        vals = method_to_test()
        print(len(vals))
        return vals



  results = mocking_instances()

tests/test_immodvisor.py:48:

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../../.venv/local/lib/python2.7/site-packages/mock/mock.py:1305: in patched
return func(args, **keywargs)
../../.venv/local/lib/python2.7/site-packages/django_mock_queries/mocks.py:299: in absorb_mocks
return target(test_case)
tests/test_immodvisor.py:42: in mocking_instances
vals = method_to_test()
tests/test_immodvisor.py:30: in method_to_test
experts = Expert.objects.filter(Q(firstname__iregex='^a.'))
../../.venv/local/lib/python2.7/site-packages/django_mock_queries/query.py:108: in filter
results = self._filter_q(results, x)
../../.venv/local/lib/python2.7/site-packages/django_mock_queries/query.py:96: in _filter_q
results = merge(results, filtered)
../../.venv/local/lib/python2.7/site-packages/django_mock_queries/utils.py:13: in merge
return first + list(set(second) - set(first))
../../.venv/local/lib/python2.7/site-packages/django_mock_queries/query.py:415: in hash
return hash_dict(self)
../../.venv/local/lib/python2.7/site-packages/django_mock_queries/utils.py:282: in hash_dict
return hash(tuple(sorted((k, v) for k, v in obj_values.items() if not fields or k in fields)))

---

self = <User: testquqwlb>

def __hash__(self):
    if self._get_pk_val() is None:
       raise TypeError("Model instances without primary key value are unhashable")

E TypeError: Model instances without primary key value are unhashable

../../.venv/local/lib/python2.7/site-packages/django/db/models/base.py:615: TypeError
1 failed in 0.65 seconds

[stphivos]

From m = MockModel(firstname='a' + exp.firstname, user=exp.user) does exp.user have a pk/id? It should work if that is populated or if the user=... part is omitted.

The library determines the hash value of a MockModel by hashing a tuple consisting of all attribute key/value pairs. If one of those values such as user happens to be a Django model, it ends up calling Django's Model.__hash__ which expects the model to have a pk.

So I think the best way is to change the library's code to determine a Model's hash depending on:

• if it's a Django model i.e. Expert to use Django's built-in way.
• if it's a MockModel, since no pk is mandatory, to keep doing the current approach.