def test_kw_arg_reset(): X = np.linspace(0, 1, num=10).reshape((5, 2)) F = FunctionTransformer(np.around, kw_args=dict(decimals=3)) F.kw_args = dict(decimals=1) # Test that rounding is correct assert_array_equal(F.transform(X), np.around(X, decimals=1))