def _mask_tester(norm_instance, vals):
 masked_array = np.ma.array(vals)
 masked_array[0] = np.ma.masked
 assert_array_equal(masked_array.mask, norm_instance(masked_array).mask)

def _mask_tester ( norm_instance , vals ) : masked_array = np . ma . array ( vals ) masked_array [ 0 ] = np . ma . masked assert_array_equal ( masked_array . mask , norm_instance ( masked_array ) . mask )
checks mask handling .