Add a README about ci tests and pkg release (to complete).

README-tests-ci-release.md

+# Automatic testing and continuous integration of FAµST with Gitlab
+
+This document briefly describes the tests, continuous integration
+and maintenance related elements for the FAµST project.
+There are specific tests for each package/language used in the project. You'll
+find a section for each one of them in the next of this document.
+
+### Summary
+1. [Test policy on Gitlab](#gitlab_pol_test)  
+2. [Testing pyfaust/matfaust](#py_matfaust_tests)  
+2.1 [Test scripts for pyfaust/matfaust](#py_matfaust_tests)  
+2.2 [Gitlab continuous integration (ci) job](#py_mat_test_ci_jobs)  
+2.3 [Test report on Gitlab pages](#py_mat_test_reports)  
+2.4 [Doctest](#doctest)  
+3. [FAµST C++ core tests](#cpp_tests)  
+4. [Package tests and automatic release](#test_release_packages)  
+
+<a name="gitlab_pol_test"/>
+
+**1. Test policy on Gitlab**
+
+A strongly strict policy is applied on Gitlab test jobs.
+The goal is to ensure the non-regression of the project (which has a large base of
+code) and limit avoidable bugged release.
+In practice, if any test, unit test or doctest fails during a test job then it won't pass
+on Gitlab, the pipeline will be marked as a failed pipeline (so it is reliable
+and instantaneous to verify all's ok).
+The failed tests are clearly indicated in the job output or into the test report
+(see below for how to find the test reports on gitlab).
+A Gitlab pipeline failure means no package will be generated or at least that
+they won't/shouldn't reach the release stage.
+
+**Note**: it is possible for a maintainer of the project to ignore some tests
+results and push a git-tag to release new packages but in that case at least
+the packages tests must pass or it will fail).
+
+**2. Testing pyfaust/matfaust**  
+
+
+**<a name="py_matfaust_tests">
+2.1 Test scripts for pyfaust/matfaust
+</a>**
+
+- Location directory: ``misc/test/src/Python`` for pyfaust and
+  ``misc/test/src/Matlab``
+  for matfaust.
+
+**Note**: at the time of writing, only 5/18 of the pyfaust's test scripts and 8/13
+of matfaust's are integrated in the automatic tests. The other scripts cover other
+needs (e.g. benchmark, debug, etc.).
+Because these scripts are old there is no guaranty they still work (maybe an update to
+recent FAµST API is needed).
+
+- Unit tests:
+    * ``test_FaustPy.py`` (124 unit tests at the time of writing for
+      ``pyfaust.Faust`` class and all algorithms/functions),
+    * ``FaustTest.m`` (31 unit tests for the ``matfaust.Faust`` class), ``FaustFactoryTest.m`` (39 unit tests for factorizations and other algorithms).
+
+- Test coverage: TODO
+
+**<a name="py_mat_test_ci_jobs">
+2.2 Gitlab continuous integration (ci) job
+</a>**
+
+- All ci jobs are defined in the ``.gitlab-ci.yml`` file.
+- Gitlab ci jobs: ``ctest_python`` for pyfaust, ``ctest_matlab`` for matfaust.
+- how it works:
+  [ctest](https://cmake.org/cmake/help/book/mastering-cmake/chapter/Testing%20With%20CMake%20and%20CTest.html)
+  is triggered by the ci job and after a building step it
+  executes (on a Linux/MacOS VM) the test and unit tests above and other test scripts.
+  The configuration of ctest for running the tests is located in ``misc/test/CMakeLists.txt``
+
+**<a name="py_mat_test_reports">
+2.3 Test reports on Gitlab pages
+</a>**
+
+- On the end of ``ctest_python``/``ctest_matlab`` execution a test report in HTML
+  is automatically uploaded to the project Gitlab pages (as a hidden page).
+  The link is displayed in the ci job output (the finished jobs are listed
+  [here](https://gitlab.inria.fr/faustgrp/faust/-/jobs)).
+  Here is [an example of report for pyfaust](https://faustgrp.gitlabpages.inria.fr/-/faust/-/jobs/3163959/artifacts/build_FaustLinuxPython/python_pyfaust_test_output.html)
+  (if this link doesn't work, the associated pipeline has been deleted on Gitlab,
+  please look [here](https://gitlab.inria.fr/faustgrp/faust/-/jobs) for a recent ``ctest_python``/``ctest_matlab`` output).
+
+**<a name="doctest">
+2.4 Doctest
+</a>**
+
+The pyfaust/matfaust API comes with many examples integrated on the [documentation](https://faustgrp.gitlabpages.inria.fr/faust/last-doc/html/index.html).
+They are all fully tested in the
+``doctest_nightly_pyfaust``/``doctest_nightly_matfaust`` ci job (cf. ``gitlab-ci.yml``)
+and comply with the job passing policy exposed in [1.](#gitlab_pol_test) (any doctest failure means the ci pipeline
+fails). These ci jobs are [scheduled](https://gitlab.inria.fr/faustgrp/faust/-/pipeline_schedules)
+to run every night.
+If any of the tested pyfaust/matfaust submodules or functions fails (and they are all tested at the time of
+writing), the erroneous tests will be displayed in the ci job output.
+
+**<a name="cpp_tests">
+3. FAµST C++ core tests
+</a>**
+
+TODO
+
+**<a name="test_release_packages">
+4. Package tests and automatic release
+</a>**
+
+TODO