add custom GitHub Actions workflow to run tests with Python 3.6 in Ubuntu 20.04 container

.github/workflows/unit_tests_python36.yml

@@ -0,0 +1,82 @@
+# documentation: https://help.github.com/en/articles/workflow-syntax-for-github-actions
+name: EasyBuild framework unit tests (Python 3.6)
+on: [push, pull_request]
+
+permissions:
+  contents: read # to fetch code (actions/checkout)
+
+concurrency:
+  group: ${{format('{0}:{1}:{2}', github.repository, github.ref, github.workflow)}}
+  cancel-in-progress: true
+
+jobs:
+  test_python36:
+    runs-on: ubuntu-latest
+    container:
+      # Ubuntu 20.04 container that already includes Python 3.6 + Lmod & co,
+      # see https://github.com/easybuilders/easybuild-containers
+      image: ghcr.io/easybuilders/ubuntu-20.04-python36-amd64
+    steps:
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
+
+    - name: install Python packages
+      run: |
+        # Python packages
+        python3.6 -V
+        python3.6 -m pip --version
+        python3.6 -m pip install --upgrade pip
+        python3.6 -m pip --version
+        python3.6 -m pip install -r requirements.txt
+        # git config is required to make actual git commits (cfr. tests for GitRepository)
+        sudo -u easybuild git config --global user.name "GitHub Actions"
+        sudo -u easybuild git config --global user.email "[email protected]"
+        sudo -u easybuild git config --get-regexp 'user.*'
+
+    - name: install GitHub token (if available)
+      env:
+        # token (owned by @boegelbot) with gist permissions (required for some of the tests for GitHub integration);
+        # this token is not available in pull requests, so tests that require it are skipped in PRs,
+        # and are only run after the PR gets merged
+        GITHUB_TOKEN: ${{secrets.CI_UNIT_TESTS_GITHUB_TOKEN}}
+      run: |
+        # tests that require a GitHub token are skipped automatically when no GitHub token is available
+        if [ ! -z $GITHUB_TOKEN ]; then
+          sudo -u easybuild python3.6 -c "import keyring; import keyrings.alt.file; keyring.set_keyring(keyrings.alt.file.PlaintextKeyring()); keyring.set_password('github_token', 'easybuild_test', '$GITHUB_TOKEN')";
+          echo "GitHub token installed!"
+        else
+          echo "Installation of GitHub token skipped!"
+        fi
+
+    - name: install sources
+      run: |
+          # install from source distribution tarball, to test release as published on PyPI
+          python3.6 setup.py sdist
+          ls dist
+          export PREFIX=/tmp/$USER/$GITHUB_SHA
+          python3.6 -m pip install --prefix $PREFIX dist/easybuild-framework*tar.gz
+
+    - name: run test suite
+      run: |
+          # run tests *outside* of checked out easybuild-framework directory,
+          # to ensure we're testing installed version (see previous step)
+          cd $HOME
+          # make sure 'eb' is available via $PATH, and that $PYTHONPATH is set (some tests expect that)
+          export PREFIX=/tmp/$USER/$GITHUB_SHA
+          ENV_CMDS="export PATH=$PREFIX/bin:$PATH; export PYTHONPATH=$PREFIX/lib/python3.6/site-packages:$PYTHONPATH"
+          ENV_CMDS="${ENV_CMDS}; export EB_VERBOSE=1; export EB_PYTHON=python3.6"
+          # run EasyBuild command via (non-root) easybuild user + login shell
+          sudo -u easybuild bash -l -c "${ENV_CMDS}; module --version; eb --version"
+          # show active EasyBuild configuration
+          sudo -u easybuild bash -l -c "${ENV_CMDS}; eb --show-config"
+          # gather some useful info on test system
+          sudo -u easybuild bash -l -c "${ENV_CMDS}; eb --show-system-info"
+          # check GitHub configuration
+          sudo -u easybuild bash -l -c "${ENV_CMDS}; eb --check-github --github-user=easybuild_test"
+          # create file owned by root but writable by anyone (used by test_copy_file)
+          sudo touch /tmp/file_to_overwrite_for_easybuild_test_copy_file.txt
+          sudo chmod o+w /tmp/file_to_overwrite_for_easybuild_test_copy_file.txt
+          # run test suite (via easybuild user + login shell)
+          sudo -u easybuild bash -l -c "${ENV_CMDS}; python3.6 -O -m test.framework.suite"
+          # There may be encoding errors in Python 3 which are hidden when an UTF-8 encoding is set
+          # Hence run the tests (again) with LC_ALL=C and Python 3.6 (or any < 3.7)
+          sudo -u easybuild bash -l -c "${ENV_CMDS}; export LC_ALL=C; python3.6 -O -m test.framework.suite"