The generage_antisymm_generator function returns zero matrix instead of random matrix. https://github.com/quantumlib/OpenFermion-FQE/blob/109a86418003fb14ee4aea9c88ffc1cd25d28d47/tests/generalized_doubles_factorization_test.py#L36 So, the test_generalized_doubles() is testing against zero matrix.