Question

I decided to look a bit into python. I found this book began to read it and did some exercises from it. Now I’m stuck at chapter 6, exactly here.
Sorry for my newbie question but where comes this test()-function from?

def mysum(xs):
    """ Sum all the numbers in the list xs, and return the total. """
    running_total = 0
    for x in xs:
        running_total = running_total + x
    return running_total

#add tests like these to your test suite ...
test(mysum([1, 2, 3, 4]), 10)
test(mysum([1.25, 2.5, 1.75]), 5.5)
test(mysum([1, -2, 3]), 2)
test(mysum([ ]), 0)
test(mysum(range(11)), 55)    # Remember that 11 is not in the list that range generates.

I can’t seem to find it and its never mentioned earlier in the book. I only found a module named test. Now I’m kind of confused, am I missing something? There is also a version of this book for Python 2.x which does not use this function in Chapter 6….
Please enlighten a newbie and sorry again for this weird question.

Answer 1

Its in Section 6.7 of the linked chapter.

def test(actual, expected):
    """ Compare the actual to the expected value,
        and print a suitable message.
    """
    import sys
    linenum = sys._getframe(1).f_lineno   # get the caller's line number.
    if (expected == actual):
        msg = "Test on line {0} passed.".format(linenum)
    else:
        msg = ("Test on line {0} failed. Expected '{1}', but got '{2}'."
                                     . format(linenum, expected, actual))
    print(msg)