Quantity sublcassing tests

testqty.py

#http://stackoverflow.com/questions/17444657/how-to-prevent-numpy-from-splitting-up-an-array-like-object

class Quantity(object):

    def __init__(self, value, unit):
        self.unit = unit
        self.value = value

    def __getitem__(self, key):
        return Quantity(self.value[key], unit=self.unit)

    def __len__(self):
        return len(self.value)

    def __array__(self):
        return self.value

    def __array_wrap__(self, arr, context=None):
        return Quantity( np.ndarray.__array_wrap__(self.value, arr, context), self.unit)

    __array_priority__ = 1000

    def __repr__(self):
        return "<Quantity "+repr(self.value)+" at "+str(id(self))+">"

import numpy as np
q = Quantity(np.array([1,2,3],dtype='float'), 'degree')
print "array(q):   ",
print(repr(np.array(q)))

print "q * [1,3,5]:",
print(repr(q * np.array([1,3,5])))
print "[1,3,5] * q:",
print(repr(np.array([1,3,5]) * q))
print "q:          ",
print(repr(q))

"""
$ python testqty.py
array(q):    array([ 1.,  2.,  3.])
q * [1,3,5]: <Quantity array([  1.,   6.,  15.]) at 4317007184>
[1,3,5] * q: <Quantity array([  1.,   6.,  15.]) at 4317007184>
q:           <Quantity array([ 1.,  2.,  3.]) at 4317007056>
"""