|Perl Monk, Perl Meditation|
RFC: Test::Contract - extensible object-oriented runtime check seriesby Dallaylaen (Hermit)
|on May 07, 2017 at 14:17 UTC||Need Help??|
Hello dear esteemed monks,
More than once I felt an urge to insert a set of Test::More's checks into my application code, for instance when loading a plug-in or validating a complex piece of data. However, Test::More/Test::Builder is best suited to only run inside test scripts.
So I came up with a module to fill the gap. And I'm going to release it to CPAN soon, unless some huge problem is detected.
The idea is as follows:
What usage I can see this far:
Some details (this is basically a copy-and-paste of the project's README):
IN-APP CHECKSThe following is going to perform some checks and output an explanation (similar to a test script output) if something went wrong.
Of course, Test::Contract can be instantiated just fine if one needs more fine-grained control.
EXTENDING THE ARSENAL
As said above, the most basic check in Test::Contract is $contract->refute( $what_went_unexpected, $why_we_care_about_it );. This may be viewed as an inverted ok or assert:
So all one needs to build a new check is to create a function that returns false when its arguments are fine, and an explanation of failure when they are not. Think pure function, although it may have side effects, e.g. checking that a file exists.
A Test::Contract::Engine::Build module exists to simplify the task further:
This would create an exported function called my_check in My::Check, as well as a my_check method in Test::Contract itself. So the following code is going to be correct:
And this one, too:
It is also possible to validate the testing module itself, outputting details on specifically the tests with unexpected results:
Using refutation instead of assertion is similar to the falsifiability concept in modern science.
Or, quoting Leo Tolstoy, "All happy families are alike; each unhappy family is unhappy in its own way".
I would be quite happy if this concept goes outside the Perl community.
As stated above, this module is going to be released to CPAN, but maybe I'm missing something very obvious here...
My previous submission on the topic: RFC: Test::Refute - extensible unified assertion & testing tool.
The project link again: https://github.com/dallaylaen/perl-test-contract.
Thank you, and hope you enjoyed the reading!