Make LearningTestTool Able to Use khiops_env if Requested

[popescu-v]

Description

Currently, kht_test.py in LearningTestTool/py does not use the settings in khiops_env.
This entails that, in order to make sure that LearningTestTool tests Khiops in (real) user-like conditions, LearningTestTool needs to replicate khiops_env settings.

For example, to match the export MPICH__INTERFACE_HOSTNAME=localhost command in khiops_env on MacOS, kht_test.py needs to detect the "Darwin" platform and replicate khiops_env behavior by adding the -host localhost options to mpiexec, which achieve the same effect (related issue on this point: #401).

The goal of this issue is to make LearningTestTool launchable in two modes:

1. a "dev" mode, which keeps the current behavior; usable:
   • by Khiops core developers, and
   • in the standard CI tests which use the MODL* binaries directly
2. a "package" / "release" mode, which executes khiops_env --env to read the MPI command (and other settings); usable:
   • in the packaging CI tests (for all platforms)
   • in the LearningTest full tests.

Context

• Khiops version: >= 10.2.3
• Scenario file (use khiops -o scenario._kh): Any
• OS description (use khiops -s): All supported

[popescu-v]

It suffices to add a --environment option that gives the path to the desired khiops_env.

[marcboulle]

Alternative simple: réutiliser le paramètre existant binaries pour y cherche le khiops_env en priorité, et si non trouvé se rabattre sur la recherche des binaires comme actuellement

[popescu-v]

Alternative simple: réutiliser le paramètre existant binaries pour y cherche le khiops_env en priorité, et si non trouvé se rabattre sur la recherche des binaires comme actuellement

Indeed, we can reuse this parameter as follows:

• if khiops_env is found in the binaries directory, then the paths to the Khiops MODL_* and MODL_Coclustering binaries can be updated according to the values of the KHIOPS_PATH and KHIOPS_COCLUSTERING_PATH environment variables, respectively;
• otherwise, the current behavior is kept.

Concretely, the changes would need to be done in the kht_test.py / build_tool_exe_path function, in the form of an if / else test on the existence of khiops_env in the tool_binaries_dir directory:

• if khiops_env is found inside tool_binaries_dir, then:
  • if tool_name equals KHIOPS, then assign tool_exe_path the value of KHIOPS_PATH;
  • else, if tool_name equals COCLUSTERING, then assign tool_exe_path the value of KHIOPS_COCLUSTERING_PATH;
    accessorily:
  • check whether these paths actually exist and update error_message accordingly if at least one of them does not;
  • update os.environ according to the output of tool_binaries_dir/khiops_env --env;
    • then, the os.environ["KHIOPS_MPI_COMMAND"]" would need to be used in the kht_test.py / evaluate_tool_on_test_dir function in order to update khiops_params; also, the other updates of os.environ with the various MPI-specific variables could be removed;
• else, keep the current behavior unchanged.