[Tutor] Testing print

[boB Stepp]

On Fri, Sep 30, 2016 at 5:07 AM, Steven D'Aprano <steve at pearwood.info> wrote:
> On Thu, Sep 29, 2016 at 09:24:51PM -0500, boB Stepp wrote:

>> Second, it seems that prints are often intermingled with the main
>> logic of a function and only serve to pass on a message to the user.
>
> Yeah, you normally shouldn't do that. Imagine if every time you called
> len(something), the len function was chatty and decided to print
> something. It would make it really hard to print anything where len() is
> involved as part of the calculation. Say I want to print a formatted
> table:
>
>     --------  --------  --------
>     COLUMN 1  COLUMN 2  COLUMN 3
>     --------  --------  --------
>     alpha     second    gamma
>               letter
>     --------  --------  --------
>
> but got something like:
>
>
>     hi this is len I just wanted to let you know I'm working hard
> -------- hi this is len I just wanted to let you know I'm working hard
> -------- hi this is len I just wanted to let you know I'm working hard
> --------
>     hi this is len I just wanted to let you know I'm working hard COLUMN
> 1 hi this is len oops something went wrong but that's okay I fixed it
> COLUMN 2 hi this is len I just wanted to let you know I'm working really
> hard you ought to be grateful okay COLUMN 3
>     hi this is len I just wanted to let you know I'm working hard
> -------- hi this is len ...

<GRIN>  You're a funny guy, Steve!  I must confess, I have been very
cavalier in using prints in my functions.  It was not until I was
trying to imagine last night how to test the example function I gave
that it truly dawned on me that this has been a baaaaad practice on my
part.  This TDD practice has been making me think about my coding
efforts in ways that I never considered previously.  Testing is a
very, very good thing!

Thanks, Steve!



-- 
boB