def test_attributes_reverse(self):
        query = """
        OUTPUT(a) :- {edge}(a, b), {emp}(c, a, x, y), c=b
        """.format(emp=self.emp_key, edge=self.edge_key)
        expected = collections.Counter(
            [(a,)
             for (a, b) in self.edge_table
             for (c, a2, x, y) in self.emp_table
             if (a == a2 and b == c)]
        )
        self.check_result(query, expected)
test that attributes are correct amid multiple conditions and when
dataset/ETHPy150Open uwescience/raco/raco/datalog/query_tests.py/TestQueryFunctions.test_attributes_reverse