Some example code showing unexpected behavior of __array_wrap__ in a subclass of np.matrix

matrix_array_wrap_test.py

import numpy as np

class ArrSubClass(np.ndarray):
    def __new__(cls, input_var):
        obj = np.ndarray(input_var).view(cls)
        return obj
    def __array_wrap__(self, obj):
        raise AssertionError

class MatSubClass(np.matrix):
    def __new__(cls, input_var):
        obj = np.matrix(input_var).view(cls)
        return obj
    def __array_wrap__(self, obj):
	raise AssertionError

def run_test(obj_creation_strs = ['o=ArrSubClass(2)',
                                   'o=MatSubClass([1, 1])',
                                   'o=MatSubClass([1.0, 1.0])',],
              obj_use_strs = ['o2 = o + 2', 'o2 = o + 2.0', 
                              'o2 = o * 2', 'o2 = o * 2.0', 
                              'o2 = o * o.T',
                              'o2 = np.dot(o,2)',
                              'o2 = np.dot(o,2.0)',
                              'o2 = np.dot(o,o.T)', 
                              'o2 = np.core.multiarray.dot(o,2)',
                              'o2 = np.core.multiarray.dot(o,2.0)',
                              'o2 = np.core.multiarray.dot(o,o.T)'] ):

    str_fmt = '{0:10s} |  {1:30s} |  {2:20s}'
    print str_fmt.format('aw called?', 'creation', 'use')
    for create_str in obj_creation_strs:
        print
	for use_str in obj_use_strs:
            exec(create_str)
            try:
                exec(use_str)
            except AssertionError:
                print str_fmt.format('Yes', create_str, use_str)
            else:
                print str_fmt.format('No', create_str, use_str)