[bugfix] Fix default executable assignment

[jjotero]

RunOnlyRegressionTest classes must be able to set the executable variable as required. However, this variable was set a default value during class instantiation. This assignment has now been moved into the compile stage.

closes #2106

[teojgo]

Since the executable is required now, you should add an executable here: https://github.com/eth-cscs/reframe/blob/8a9ceeda69619d367820d5297f5018183d52a897/unittests/test_policies.py#L139 and maybe do the same for the resources of the unittests.

[teojgo]

@jjotero @vkarak Do you think that we should also mention that the executable is required for the RunOnlyRegressionTest in the tutorial?

[codecov-commenter]

Codecov Report

Merging #2107 (7b0cba9) into master (a2870ca) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2107      +/-   ##
==========================================
+ Coverage   86.23%   86.24%   +0.01%     
==========================================
  Files          53       53              
  Lines        9305     9305              
==========================================
+ Hits         8024     8025       +1     
+ Misses       1281     1280       -1     

Impacted Files	Coverage Δ
reframe/core/pipeline.py	91.90% <100.00%> (+0.16%)	⬆️

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[jjotero]

@teojgo I think it could add that in the regression test API docs instead. Like a version changed box or something like that.

[vkarak]

@jjotero @teojgo I think that a small note in the tutorial to alert the readers would be good.

[vkarak]

Lgtm now. I've done a minor rephrase in the docs.

[ireed]

Is there a way to use two self.executable values in a single test? For example, if i want to run two different programs, how can i do something like self.executable1='prog1', self.executable2='prog2' with both appearing in the same submission script? This is to avoid a hack such as self.executable='prog1\nsrun prog2', which i do quite often, but is not portable.

[teojgo]

Is there a way to use two self.executable values in a single test? For example, if i want to run two different programs, how can i do something like self.executable1='prog1', self.executable2='prog2' with both appearing in the same submission script? This is to avoid a hack such as self.executable='prog1\nsrun prog2', which i do quite often, but is not portable.

If you want to run to executables with the same srun options then you can put the executable commands inside a bash script run.sh and then set the executable as 'run.sh'.

[vkarak]

@ireed You may also have a look on how to create scripts with multiple parallel launcher commands: https://reframe-hpc.readthedocs.io/en/stable/tutorial_advanced.html#adding-more-parallel-launch-commands