simplify test_fixed_length_array_expression
simplify test_fixed_length_array_expression

rootpy/root_numpy,ndawe/root_numpy,ndawe/root_numpy,ndawe/root_numpy,scikit-hep/root_numpy,scikit-hep/root_numpy,rootpy/root_numpy,rootpy/root_numpy,ndawe/root_numpy,scikit-hep/root_numpy,scikit-hep/root_numpy,rootpy/root_numpy