Update coverage collection

Author: PicoCentauri

.github/workflows/tests.yml

@@ -26,7 +26,9 @@ jobs:
       run: python -m pip install tox
 
     - name: run Python tests
-      run: tox -e tests
+      run: |
+        tox -e tests
+        coverage xml
 
     - name: upload to codecov.io
       uses: codecov/codecov-action@v5

pyproject.toml

@@ -86,7 +86,12 @@ known_first_party = "skmatter"
 
 [tool.pytest.ini_options]
 testpaths = ["tests"]
-addopts = ["--cov"]
+addopts = [
+    "--cov",
+    "--cov-append",
+    "--cov-report=",
+    "--import-mode=append",
+]
 
 [tool.ruff]
 exclude = ["docs/src/examples/"]