Re: I love assert

References	<96c138e4-ab95-4e5f-a0c8-e696b5a926bb@googlegroups.com>
From	TP <wingusr@gmail.com>
Date	2014-11-27 01:22 -0800
Subject	Re: I love assert
Newsgroups	comp.lang.python
Message-ID	<mailman.16362.1417080206.18130.python-list@python.org> (permalink)

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On Tue, Nov 11, 2014 at 11:40 AM, Peter Cacioppi <peter.cacioppi@gmail.com>
wrote:

> I get the impression that most Pythonistas aren't as habituated with
> assert statements as I am. Is that just a misimpression on my part? If not,
> is there a good reason to assert less with Python than other languages?
>
> As far as I can tell, Python supports assert perfectly well. When run with
> the optimization flagging, the asserts are truly removed.
>
> I think one needs to take care with some basic assert coding - it's not a
> substitute for unit tests, it doesn't absolve you of normal exception
> responsibilities, and, most of all, it should be used for passive
> inspection and not action. But given these guidelines, I still find it very
> useful as "active comments".
>

In "Why Most Unit Testing is Waste" by James O Coplien [1] he says on page
10:

"However, as with most unit tests, it's better to make this an assertion
than to pepper your test framework with such checks."

page 15:

"When I look at most unit tests -- especially those written with JUnit --
they are assertions in disguise. When I write a great piece of software I
sprinkle it with assertions that describe promises that I expect the
callers of my functions to live up to, as well as promises that function
makes to its clients. Those assertions evolve in the same artefact as the
rest of my code."

page 16:

"An even more professional approach is to leave the assertions in the code
when you ship, and to automatically file a bug report on behalf of the end
user and perhaps to try to re-start the application every time an assertion
fails."

"Turn unit tests into assertions. Use them to feed your fault-tolerance
architecture on high-availability systems. This solves the problem of
maintaining a lot of extra software modules that assess execution and check
for correct behavior; that's one half of a unit test. The other half is the
driver that executes the code: count on your stress tests, integration
tests, and system tests to do that."

And in "Seque" by James O Coplien [2] he is even more emphatic on page 17:

"This argumentation, of course, is just an alternative justification for
the use of assertions in the code, as we already introduced in Chapter 1.
Assertions are powerful unit-level guards that beat most unit tests in two
ways. First, each one can do the job of a large number (conceivably,
infinite) of scenario-based unit tests that compare computational results
to an oracle. Second, they extend the run time of the test over a much
wider range of contexts and detailed scenario variants by extending the
test into the lifetime of the product."

[1] http://www.rbcs-us.com/documents/Why-Most-Unit-Testing-is-Waste.pdf

[2] http://www.rbcs-us.com/documents/Segue.pdf

Thread

I love assert Peter Cacioppi <peter.cacioppi@gmail.com> - 2014-11-11 11:40 -0800
  Re: I love assert Ben Finney <ben+python@benfinney.id.au> - 2014-11-12 07:03 +1100
    Re: I love assert Grant Edwards <invalid@invalid.invalid> - 2014-11-11 21:43 +0000
  Re: I love assert Ethan Furman <ethan@stoneleaf.us> - 2014-11-11 12:08 -0800
  Re: I love assert Rob Gaddi <rgaddi@technologyhighland.invalid> - 2014-11-11 12:20 -0800
  Re: I love assert Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-11-11 20:34 +0000
  Re: I love assert TP <wingusr@gmail.com> - 2014-11-11 12:57 -0800
  Re: I love assert Terry Reedy <tjreedy@udel.edu> - 2014-11-11 17:34 -0500
  Re: I love assert Ben Finney <ben+python@benfinney.id.au> - 2014-11-12 09:52 +1100
  Re: I love assert Tim Chase <python.list@tim.thechases.com> - 2014-11-11 17:03 -0600
  Re: I love assert Peter Cacioppi <peter.cacioppi@gmail.com> - 2014-11-11 15:02 -0800
  Re: I love assert Ethan Furman <ethan@stoneleaf.us> - 2014-11-11 15:38 -0800
  Re: I love assert Dan Stromberg <drsalists@gmail.com> - 2014-11-11 17:56 -0800
  Re: I love assert Chris Angelico <rosuav@gmail.com> - 2014-11-12 13:21 +1100
  Re: I love assert Ben Finney <ben+python@benfinney.id.au> - 2014-11-12 13:35 +1100
    Re: I love assert Grant Edwards <invalid@invalid.invalid> - 2014-11-12 14:10 +0000
  Re: I love assert Chris Angelico <rosuav@gmail.com> - 2014-11-12 13:44 +1100
    Re: I love assert wxjmfauth@gmail.com - 2014-11-11 23:14 -0800
  Re: I love assert Terry Reedy <tjreedy@udel.edu> - 2014-11-12 03:29 -0500
  Re: I love assert Anton <anton.schattenfeld@gmail.com> - 2014-11-12 12:53 -0800
    Re: I love assert Marko Rauhamaa <marko@pacujo.net> - 2014-11-12 23:41 +0200
      Re: I love assert Ethan Furman <ethan@stoneleaf.us> - 2014-11-12 13:52 -0800
        Re: I love assert Marko Rauhamaa <marko@pacujo.net> - 2014-11-12 23:56 +0200
          Re: I love assert Ian Kelly <ian.g.kelly@gmail.com> - 2014-11-12 15:04 -0700
            Re: I love assert Anton <anschatten@gmail.com> - 2014-11-12 14:13 -0800
              Re: I love assert Ian Kelly <ian.g.kelly@gmail.com> - 2014-11-12 15:41 -0700
                Re: I love assert Anton <anschatten@gmail.com> - 2014-11-12 14:48 -0800
                Re: I love assert Marko Rauhamaa <marko@pacujo.net> - 2014-11-13 01:01 +0200
                Re: I love assert Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-11-15 10:40 +1100
                Re: I love assert Marko Rauhamaa <marko@pacujo.net> - 2014-11-15 02:12 +0200
                Re: I love assert Chris Angelico <rosuav@gmail.com> - 2014-11-15 12:04 +1100
                Re: I love assert Marko Rauhamaa <marko@pacujo.net> - 2014-11-15 03:30 +0200
                Re: I love assert Chris Angelico <rosuav@gmail.com> - 2014-11-15 12:48 +1100
                Re: I love assert Tim Chase <python.list@tim.thechases.com> - 2014-11-14 20:14 -0600
                Re: I love assert Chris Angelico <rosuav@gmail.com> - 2014-11-15 13:16 +1100
                Re: I love assert albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-11-29 17:35 +0000
                Re: I love assert Ian Kelly <ian.g.kelly@gmail.com> - 2014-11-12 16:02 -0700
                Re: I love assert Anton <anschatten@gmail.com> - 2014-11-12 15:43 -0800
                Re: I love assert Chris Angelico <rosuav@gmail.com> - 2014-11-13 10:10 +1100
                Re: I love assert Marko Rauhamaa <marko@pacujo.net> - 2014-11-13 01:23 +0200
                Re: I love assert Chris Angelico <rosuav@gmail.com> - 2014-11-13 10:27 +1100
                Re: I love assert Marko Rauhamaa <marko@pacujo.net> - 2014-11-13 01:31 +0200
              Re: I love assert Ethan Furman <ethan@stoneleaf.us> - 2014-11-12 14:47 -0800
                Re: I love assert Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-11-14 22:37 +1100
                Re: I love assert Ian Kelly <ian.g.kelly@gmail.com> - 2014-11-14 09:40 -0700
          Re: I love assert Ian Kelly <ian.g.kelly@gmail.com> - 2014-11-12 15:07 -0700
            Re: I love assert Marko Rauhamaa <marko@pacujo.net> - 2014-11-13 00:47 +0200
              Re: I love assert Ethan Furman <ethan@stoneleaf.us> - 2014-11-12 14:56 -0800
              Re: I love assert Chris Angelico <rosuav@gmail.com> - 2014-11-13 09:58 +1100
              Re: I love assert Ian Kelly <ian.g.kelly@gmail.com> - 2014-11-12 16:05 -0700
                Re: I love assert Marko Rauhamaa <marko@pacujo.net> - 2014-11-13 01:12 +0200
              Re: I love assert Lie Ryan <lie.1296@gmail.com> - 2014-11-14 01:09 +1100
        Re: I love assert Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-11-14 22:33 +1100
          Re: I love assert Ethan Furman <ethan@stoneleaf.us> - 2014-11-14 10:18 -0800
            Re: I love assert Marko Rauhamaa <marko@pacujo.net> - 2014-11-14 21:12 +0200
              Re: I love assert Ethan Furman <ethan@stoneleaf.us> - 2014-11-14 12:41 -0800
                Re: I love assert Marko Rauhamaa <marko@pacujo.net> - 2014-11-14 22:50 +0200
            Re: I love assert Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-11-15 13:58 +1100
              Re: I love assert Ethan Furman <ethan@stoneleaf.us> - 2014-11-14 20:09 -0800
                Re: I love assert Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-11-17 13:09 +1100
                Re: I love assert Ethan Furman <ethan@stoneleaf.us> - 2014-11-16 19:25 -0800
      Re: I love assert Anton <anschatten@gmail.com> - 2014-11-12 14:00 -0800
        Re: I love assert Anton <anschatten@gmail.com> - 2014-11-12 14:04 -0800
          Re: I love assert Marko Rauhamaa <marko@pacujo.net> - 2014-11-13 00:34 +0200
    Re: I love assert Chris Angelico <rosuav@gmail.com> - 2014-11-13 09:43 +1100
  Re: I love assert Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-11-14 22:15 +1100
  Re: I love assert Richard Riehle <rriehle@itu.edu> - 2014-11-14 14:09 -0800
    Decorators (was: Re: I love assert) Marko Rauhamaa <marko@pacujo.net> - 2014-11-15 00:18 +0200
      Re: Decorators Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-11-14 22:37 +0000
        Re: Decorators Marko Rauhamaa <marko@pacujo.net> - 2014-11-15 00:47 +0200
      Re: Decorators (was: Re: I love assert) Richard Riehle <rriehle@itu.edu> - 2014-11-14 18:19 -0800
        Re: Decorators (was: Re: I love assert) Mayank Tripathi <oquanox@gmail.com> - 2014-11-15 02:36 +0000
        Re: Decorators (was: Re: I love assert) Tim Chase <python.list@tim.thechases.com> - 2014-11-14 20:30 -0600
          Re: Decorators Marko Rauhamaa <marko@pacujo.net> - 2014-11-15 09:00 +0200
            Re: Decorators Grant Edwards <invalid@invalid.invalid> - 2014-11-15 15:32 +0000
        Re: Decorators (was: Re: I love assert) Richard Riehle <rriehle@itu.edu> - 2014-11-14 23:42 -0800
        Re: Decorators Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-11-15 13:12 +0000
          Re: Decorators Marko Rauhamaa <marko@pacujo.net> - 2014-11-15 15:24 +0200
            Re: Decorators Terry Reedy <tjreedy@udel.edu> - 2014-11-15 15:28 -0500
        Re: Decorators (was: Re: I love assert) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-11-16 02:39 +1100
  Re: I love assert TP <wingusr@gmail.com> - 2014-11-27 01:22 -0800
    Re: I love assert alister <alister.nospam.ware@ntlworld.com> - 2014-11-27 09:59 +0000
      Re: I love assert Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-11-29 12:30 +1100
        Re: I love assert MRAB <python@mrabarnett.plus.com> - 2014-11-29 02:56 +0000
          Re: I love assert Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-11-29 20:31 +1100
            Re: I love assert Chris Angelico <rosuav@gmail.com> - 2014-11-29 21:40 +1100
            Re: I love assert MRAB <python@mrabarnett.plus.com> - 2014-11-29 19:49 +0000
        Re: I love assert Chris Angelico <rosuav@gmail.com> - 2014-11-29 14:02 +1100
        Re: I love assert Ethan Furman <ethan@stoneleaf.us> - 2014-11-29 14:33 -0800
          Re: I love assert Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-11-30 19:18 +1100
            Re: I love assert Ethan Furman <ethan@stoneleaf.us> - 2014-11-30 11:34 -0800

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