ci | add github action for pytest

* help by claude

.github/workflows/pytest.yml

@@ -0,0 +1,31 @@
+name: pytest
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ['3.8', '3.9', '3.10', '3.11']
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install .[test]
+    - name: Test with pytest
+      run: |
+        pytest tests/ --doctest-modules --junitxml=junit/test-results-${{ matrix.python-version }}.xml --cov=. --cov-report=xml --cov-report=html
+    - name: Upload pytest results
+      uses: actions/upload-artifact@v3
+      with:
+        name: pytest-results-${{ matrix.python-version }}
+        path: junit/test-results-${{ matrix.python-version }}.xml
+      if: ${{ always() }}
+