[erlang-questions] Do you know what your code is doing at night?

Jesper Louis Andersen <>
Thu Jul 13 23:01:17 CEST 2017


The question of linking unit tests and property based testing has been
covered by Gerdes, Hughes, Smallbone, and Wang:

http://www.cse.chalmers.se/~nicsma/papers/unit-tests.pdf

The idea here is to ask: Suppose we have a property based test suite and a
set of unit tests. Can we check if the unit tests are already covered by
the property suite? The paper answers this in the affirmative. You can
construct a system which can answer the question, with great probability.

It is highly useful in the case where you have a specification and the
specification contains certain examples. By making sure your suite covers
those examples, you gain the knowledge that your suite is not totally off
w.r.t the unit test examples.

In a system with property based testing, you can often track each
counterexample you've encountered in a small suite of things to try first.
This allows you to quickly check for regressions rather than generating new
traces to try. OTOH, if you don't regularly generate the cases, then
chances are your generator is off and not being evil enough >:-)

On Thu, Jul 13, 2017 at 3:11 PM Manfred Lotz <> wrote:

> On Thu, 13 Jul 2017 07:16:06 -0400
> Fred Hebert <> wrote:
>
> > On 07/13, Manfred Lotz wrote:
> > >I think Fred could add a section "Unit testing versus property based
> > >testing" and add your explanations.
> > >
> >
> > Similar content is already part of the book, though not necessarily
> > in a dedicated section.
>
> I think it is worth to make your and Loic's answer a dedicated section
> or subsection.
>
>
> --
> Manfred
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> 
> http://erlang.org/mailman/listinfo/erlang-questions
>
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