ci(tox.yml): add tox moderated pytest check p310...py314

To prove appendfile's work, checks by pytest can be run on
GitHub's os runners of macos, ubuntu, windows in permutation
of Python interpreters Py 3.10...3.14 (if available).

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

.github/workflows/tox.yml

@@ -0,0 +1,39 @@
+name: CI_tox_appendfilename
+
+# name    : tox.yml
+# purpose : run pytest on appendfilename
+# date    : [2026-05-13 Wed]
+# edit    :
+
+on:
+  workflow_dispatch:  # the manual trigger
+  # push:
+    # branches: [ dev, main ]
+
+jobs:
+  test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [macos-latest, ubuntu-latest, windows-latest]
+        python-version: ['3.10', '3.11', '3.12', '3.13', '3.14']
+
+    steps:
+    - uses: actions/checkout@v5
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v6
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Install tox
+      run: |
+        python -m pip install --upgrade pip
+        pip install .
+        pip install pytest
+        pip install tox tox-gh-actions
+        pip list
+
+    - name: run tox' jobs (which GitHub happens to split in separate jobs)
+      run: tox
+

tox.ini

@@ -0,0 +1,11 @@
+[tox]
+envlist = py310, py311, py312, py313, py314
+isolated_build = True
+ignore_missing_interpreters = True
+
+[testenv]
+deps =
+  pytest
+commands =
+  pytest
+