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Python Python Testing First Steps With Testing Create a Doctest

Devin Scheu
Devin Scheu
66,191 Points

Phython Testing

Question: Add a doctest to average() that tests the function with the list [1, 2]. Because of how we test doctests, you'll need to leave a blank line at the end of your doctest before the closing quotes.

My Code:

average.py
def average(num_list):
    """Return the average for a list of numbers

    >>> numb_list = (1, 2)
    1.5


    """
    return sum(num_list) / len(num_list)

2 Answers

this the right answer:

def average(num_list): """Return the average for a list of numbers

>>> average([1,2])
1.5


"""
return sum(num_list) / len(num_list)
Ken Alger
STAFF
Ken Alger
Treehouse Teacher

Devin;

You are not testing the function, average. The test needs to test average() with the given list of numbers to get a result of 1.5. Right now your code is assigning a value to numb_list and testing if that is equal to 1.5.

Post back if you are still stuck.

Ken

Devin Scheu
Devin Scheu
66,191 Points

Hey can you show me code (Doesn't have to be these challenges) step by step, i'm still not understanding this fully.

Ken Alger
Ken Alger
Treehouse Teacher

Devin;

Let's look at a different function to test. This will be silly because it simply renames another function, but hopefully it will make some sense.

def add_a_list(num_list):
    return sum(num_list)

Pointless, right? For our purposes though it should work. We need to test that if we do `add_a_list([5,3]) that we get the number 8 returned. Our test then, would look similar to:

def add_a_list(num_list):
    """ Return the sum of a list of numbers

    >>> add_a_list([5,3])
    8

    """
    return sum(num_list)

The Doctest then will run through the test code, inside the triple quotes, and test if our function returns what we are expecting it to. If it does, great. If it doesn't, we will get an error. Again, for this example it isn't probably super important. What if we are doing some more advanced math though?

That's probably too close to the original challenge for an example, but at the moment it's all I've got.

Post back if you're still stuck.

Ken

Devin Scheu
Devin Scheu
66,191 Points

With your help I figured it out! I was trying to set the argument inside the function, instead of passing the argument into the function in the test. On a side note, you need a space after your add_a_list([5,3]). Thanks again for your help Ken!