def test_counter_must_return_changed_value_after_document_adding(db):
c = db.collection1
c.insert({'_id':1})
assert last_id_for(c) == 1
c.insert({'_id':100})
assert last_id_for(c) == 100
def test_counter_must_return_max_value(db):
c1 = db.collection1
c2 = db.collection2
c1.insert({'_id':1})
c1.insert({'_id':2})
c2.insert({'_id':50})
assert last_id_for(c1) == 2
assert last_id_for(c2) == 50
def test_counter_must_return_zero_for_nonexisting_keys(db):
assert last_id_for(db.some_collection1) == 0
