diff --git a/.github/workflows/build-and-deploy.yml b/.github/workflows/build-and-deploy.yml
index 51aba02..8651b71 100644
--- a/.github/workflows/build-and-deploy.yml
+++ b/.github/workflows/build-and-deploy.yml
@@ -26,8 +26,9 @@ jobs:
       - name: Build wheels
         uses: pypa/cibuildwheel@v2.19.2
 
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         with:
+          name: stl-reader-wheels-${{ matrix.os }}
           path: ./wheelhouse/*.whl
 
   build_sdist:
@@ -36,11 +37,24 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+
       - name: Build sdist
         run: pipx run build --sdist
 
-      - uses: actions/upload-artifact@v3
+      - name: Install from sdist
+        run: pip install dist/stl_reader*.tar.gz
+
+      - name: Run tests
+        run: |
+          pip install pyvista pytest
+          pytest -x
+
+      - uses: actions/upload-artifact@v4
         with:
+          name: stl-reader-sdist
           path: dist/*.tar.gz
 
   upload_pypi:
@@ -48,10 +62,15 @@ jobs:
     runs-on: ubuntu-latest
     if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags')  # upload to PyPI on every tag
     steps:
-      - uses: actions/download-artifact@v3
-        with:
-          name: artifact
-          path: dist
+      - uses: actions/download-artifact@v4
+      - name: Flatten directory structure
+        run: |
+          mkdir -p dist/
+          find . -name '*.whl' -exec mv {} dist/ \;
+          find . -name '*.tar.gz' -exec mv {} dist/ \;
+
+      - name: List artifacts
+        run: ls -R
 
       - uses: pypa/gh-action-pypi-publish@v1.9.0
         with:
diff --git a/pyproject.toml b/pyproject.toml
index ffa3a77..7c0539a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -15,6 +15,7 @@ filterwarnings = [
     "ignore:.*numpy.dtype size changed.*:RuntimeWarning",
     "ignore:.*numpy.ufunc size changed.*:RuntimeWarning"
 ]
+testpaths = 'tests'
 
 [tool.cibuildwheel]
 archs = ["auto64"]  # 64-bit only
diff --git a/setup.py b/setup.py
index 2c4b259..82fd5da 100644
--- a/setup.py
+++ b/setup.py
@@ -56,6 +56,7 @@
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
+        "Programming Language :: Python :: 3.12",
     ],
     python_requires=">=3.8",
     url="https://github.com/pyvista/stl-reader",
@@ -76,7 +77,7 @@
         ]
     ),
     package_data={
-        "stl_reader": ["*.pyx"],  # include all .pyx files in the package
+        "stl_reader": ["*.pyx", "*.h", "stlfile.c", "_stlfile_wrapper.c"],
     },
     keywords="read stl",
     install_requires=["numpy>1.11.0,<2.0"],