diff --git a/.github/workflows/test_and_deploy.yml b/.github/workflows/test_and_deploy.yml
index 3c4f138..bbeb956 100644
--- a/.github/workflows/test_and_deploy.yml
+++ b/.github/workflows/test_and_deploy.yml
@@ -16,7 +16,25 @@ on:
       - npe2
   workflow_dispatch:
 
+env:
+  FORCE_COLOR: "1"
+
 jobs:
+  build-package:
+    name: Build & verify package
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: hynek/build-and-inspect-python-package@v2
+        id: baipp
+
+    ouputs:
+      # Used to define the matrix for tests below. The value is based on
+      # packaging metadata (trove classifiers).
+      python-versions: ${{ steps.baipp.outputs.supported_python_classifiers_json_array }}
+
   test:
     name: ${{ matrix.platform }} py${{ matrix.python-version }}
     runs-on: ${{ matrix.platform }}
@@ -24,15 +42,25 @@ jobs:
     strategy:
       matrix:
         platform: [ubuntu-latest, windows-latest, macos-latest]
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ${{ fromJson(needs.build-package.outputs.python-versions) }}
 
-    steps:
-      - uses: actions/checkout@v4
+    env:
+      PYTHON: ${{ matrix.python-version }}
 
-      - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v5
+    steps:
+      - name: Download pre-built packages
+        uses: actions/download-artifact@v4
+        with:
+          name: Packages
+          path: dist
+      - run: |
+          tar xf dist/*.tar.gz --strip-components=1
+          rm -rf src
+      - uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
+          allow-prereleases: true
+      - uses: hynek/setup-cached-uv@v2
 
       # these libraries enable testing on Qt on linux
       - uses: tlambert03/setup-qt-libs@v1
@@ -57,12 +85,61 @@ jobs:
       - name: Test with tox
         uses: aganders3/headless-gui@v2
         with:
-          run: python -m tox
-        env:
-          PLATFORM: ${{ matrix.platform }}
+          run: >
+            uvx --with tox-uv tox run
+            --installpkg dist/*.whl
+            -f py${PYTHON//./}-tests
+
+      # - name: Coverage
+      #   uses: codecov/codecov-action@v3
+
+      - name: Upload coverage data
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-data-${{ matrix.python-version }}
+          path: .coverage.*
+          include-hidden-files: true
+          if-no-files-found: ignore
+
+  coverage:
+    name: Ensure 90% test coverage
+    runs-on: ubuntu-latest
+    needs: test
+    if: always()
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: true
+      - uses: actions/setup-python@v5
+        with:
+          python-version-file: .python-version
+      - uses: hynek/setup-cached-uv@v2
 
-      - name: Coverage
-        uses: codecov/codecov-action@v3
+      - name: Download coverage data
+        uses: actions/download-artifact@v4
+        with:
+          pattern: coverage-data-*
+          merge-multiple: true
+
+      - name: Combine coverage and fail if it's below 90%
+        run: |
+          uv tool install 'coverage[toml]'
+
+          coverage combine
+          coverage html --skip-covered --skip-empty
+
+          # Report and write to summary
+          coverage report --format=markdown >> $GITHUB_STEP_SUMMARY
+
+          # Report again and fail if under 90%
+          coverage report --fail-under=90
+
+      - name: Upload HTML report
+        uses: actions/upload-artifact@v4
+        with:
+          name: html-report
+          path: htmlcov
 
   deploy:
     # this will run when you have tagged a commit, starting with "v*"
diff --git a/tox.ini b/tox.ini
index 51b38c3..bcf29ba 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 # For more information about tox, see https://tox.readthedocs.io/en/latest/
 [tox]
-envlist = py{39,310,311,312}-{linux,macos,windows}
+envlist = py{39,310,311,312,313}-{linux,macos,windows}
 isolated_build=true
 
 [gh-actions]
@@ -17,6 +17,8 @@ PLATFORM =
     windows-latest: windows
 
 [testenv]
+package = wheel
+wheel_build_env = .pkg
 platform =
     macos: darwin
     linux: linux