ci(pytest.yml): adopt matrix syntax of GitHub actions

The pytest based testing is redefined adopting tmatrix based syntax
GitHub offers.  This eases to track which versions of OSes and Python
interpreters are engaged, and a format is more compact, than the one
used earlier.  Inspired/partially copy-pasted from a project related
to chemistry.[1]

[1] https://github.com/nbehrnd/datawarrior_saturate_Murcko_scaffolds

Signed-off-by: Norwid Behrnd <nbehrnd@yahoo.com>

.github/workflows/pytest.yml

@@ -3,7 +3,7 @@ name: CI_pytest_appendfilename
 # name    : pytest.yml
 # purpose : regularly run pytest on appendfilename
 # date    : [2024-10-31 Thu]
-# edit    : [2024-10-31 Thu]
+# edit    : [2024-11-12 Tue]
 
 on:
   push:
@@ -17,9 +17,17 @@ on:
     # - cron: "0 0 1 * *"  # once each 1st of a month, at 00:00 UTC (cf. https://crontab.guru/)
 
 jobs:
-  test-ubuntu-2404:
-    runs-on: ubuntu-24.04
-    timeout-minutes: 5
+  test:
+    strategy:
+      matrix:
+        # for a factorial test, an explicit selection of GitHUb runner images
+        # https://github.com/actions/runner-images?tab=readme-ov-file#available-images
+        # state of commit 23478d3 as visited on 2024-11-11 Mon
+        os: [ubuntu-20.04, ubuntu-22.04,ubuntu-24.04, windows-2019, windows-2022, macos-14]
+        python-version: ["3.10", "3.12"]
+    runs-on: ${{ matrix.os }}
+
+    timeout-minutes: 5  # Timeout for each job individually
 
     steps:
       - uses: actions/checkout@v4
@@ -28,52 +36,7 @@ jobs:
 
       - uses: actions/setup-python@v5
         with:
-          python-version: '3.x'
-
-      - name: Install dependencies with PyPI
-        run: pip install -r requirements.txt
-
-      - name: run the check by pytest
-        run: |
-          python -m pytest -m "default"
-          python -m pytest -m "prepend"
-          python -m pytest -m "smart"
-
-  test-windows-2022:
-    runs-on: windows-2022
-    timeout-minutes: 5
-
-    steps:
-      - uses: actions/checkout@v4
-        # by [2024-10-23 Wed], this version possibly will be considered "old", cf.
-        # https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/
-
-      - uses: actions/setup-python@v5
-        with:
-          python-version: '3.x'
-
-      - name: Install dependencies with PyPI
-        run: pip install -r requirements.txt
-
-      - name: run the check by pytest
-        run: |
-          python -m pytest -m "default"
-          python -m pytest -m "prepend"
-          python -m pytest -m "smart"
-
-
-  test-macos-14:
-    runs-on: macos-14
-    timeout-minutes: 5
-
-    steps:
-      - uses: actions/checkout@v4
-        # by [2024-10-23 Wed], this version possibly will be considered "old", cf.
-        # https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/
-
-      - uses: actions/setup-python@v5
-        with:
-          python-version: '3.x'
+          python-version: ${{ matrix.python-version }}
 
       - name: Install dependencies with PyPI
         run: pip install -r requirements.txt