Implement simpletests

As we've seen with the recent results...

There's too less test coverage.
We've found results in which triggering a success condition in Test A triggers resulted in success counts for all other test case too...
The test cases should be extended by concurrent tests: Multiple test cases enabled to run in parallel. Triggering visits / success, checking stats.

Oops, that's a real ugly thing...
And simulating this is even more ugly...

This is out of the scope of my research till now.
We really need that stuff or we're really far away from reliable testing.

I guess we should rewrite the architecture to follow the dependency injection and add clean interfaces. Then we can provide a lot of unit tests...

Additionally we can also add some user side testing with tools like casperJS / PhantomJS...

Since both of you are going to Prague, perhaps there's enough interest for a BOF and possibly a code sprint?

Just my 2c

I won't be in prague, i'm sorry. Two of my team will be there.
In case there's a BOF, i can tell them to participate.

Our team primarily sprints for D8 core and contrib D8 conversion and they have a ton of (other) modules to convert...

I'm not too familiar with Simpletest but I did some digging and it might possibly now support handling cookies:
https://drupal.org/simpletest-tutorial-drupal7#comment-5763610
#1319736: SimpleTest: When using drupalGet to send the cookie, it's sending Cookie header twice, so the $_COOKIE is not valid

Simpletest does environment isolation based on headers to allow running multiple tests in parallel (that finally interact with complete separate installs / drupal instances...)

A simpletest supports one session at a given time. As far as i know, there's no API to simulate multiple user sessions in parallel within one simpletest.
Either this needs manual header tweaking / session switches - that additionally need simpletest environment isolation preservation OR we go completely away from simpletest and write unittests (thus test our APIs only and improve our patterns by using dependency injection (meaning, all dependent objects are injected in constructor - and not rely on globals in any kind) and test whatever we can tests - without real web requests (aka integration / simple tests).

OK, agree, it is possible with a simpletest.
Simpletest uses the user-agent header to identify the right test instance.
We can implement own session switches and simulate multiple users, but we will need to "hack" some simpletest environments to use the regular drupalGet or similar with tweaked / switches sessions.

You are right about parallel sessions - I was thinking about Session API module but it has a bit different use case. We could write tests from a single user point of view but it will not get full test coverage as the tests/combinations run will be specific to that user only.
There's also the possibility of writing simpletests for crud tasks and unit tests for the rest of the code...

I'll be in Prague Monday through Friday and am quite flexible in terms of scheduling.

Let's meet up at the BOF tomorrow and see where it goes. If there's not enough interest we can always start writing some code during the BOF