diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3803ff1..b591435 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -50,111 +50,111 @@ jobs:
       - name: ${{ matrix.task.name }}
         run: ${{ matrix.task.run }}
 
-#   coverage:
-#     name: "Test py-${{ matrix.python-version }} (${{ matrix.os }})"
-#     strategy:
-#       max-parallel: 4
-#       fail-fast: false
-#       matrix:
-#         # ignore windows for now
-#         os: [ubuntu] #, macos] # , windows-latest]
-#         python-version:
-#           - "3.9"
-#           - "3.10"
-#           - "3.11"
-#           - "3.12"
+  coverage:
+    name: "Test py-${{ matrix.python-version }} (${{ matrix.os }})"
+    strategy:
+      max-parallel: 4
+      fail-fast: false
+      matrix:
+        os: [ubuntu] 
+        python-version:
+          - "3.8"
+          - "3.9"
+          - "3.10"
+          - "3.11"
+          - "3.12"
 
 #     continue-on-error: >-
 #       ${{ contains(matrix.python-version, 'dev') && true || false }}
 
-#     runs-on: ${{ matrix.os }}-latest
-#     steps:
-#       #----------------------------------------------
-#       #       check-out repo and set-up python
-#       #----------------------------------------------
-#       - name: Check out repository
-#         uses: actions/checkout@v4
-
-#       #----------------------------------------------
-#       #  -----  install & configure python & rye  -----
-#       #----------------------------------------------
-#       - name: Set up the environment
-#         uses: ./.github/actions/setup-python-env
-#         with:
-#           python-version: ${{ matrix.python-version }}
+    runs-on: ${{ matrix.os }}-latest
+    steps:
+      #----------------------------------------------
+      #       check-out repo and set-up python
+      #----------------------------------------------
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      #----------------------------------------------
+      #  -----  install & configure python & rye  -----
+      #----------------------------------------------
+      - name: Set up the environment
+        uses: ./.github/actions/setup-python-env
+        with:
+          python-version: ${{ matrix.python-version }}
      
-#      
-#       #----------------------------------------------
-#       # Run tests and upload coverage
-#       #----------------------------------------------
-#       - name: Run tests for coverage
-#         run: make test-w-coverage
-
-#       - name: copy coverage
-#         run: |
-#           mkdir coverage
-#           cp -v .coverage coverage/.coverage.${{ matrix.os }}-py${{ matrix.python-version }}
-
-#       - name: store coverage files
-#         uses: actions/upload-artifact@v3
-#         with:
-#           name: coverage
-#           path: coverage
-
-
-#   upload-coverage:
-#     name: Upload test coverage to CodeCov
-#     needs: [coverage]
-#     runs-on: ubuntu-latest
-#     permissions:
-#       statuses: write
-#     steps:
-#       #----------------------------------------------
-#       #       check-out repo and set-up python
-#       #----------------------------------------------
-#       - name: Check out repository
-#         uses: actions/checkout@v4
-#       - name: Set up python ${{ env.MINIMUM_PYTHON_VERSION }}
-#         id: setup-python
-#         uses: actions/setup-python@v5
-#         with:
-#           python-version: ${{ env.MINIMUM_PYTHON_VERSION }}
-
-#       #----------------------------------------------
-#       # install dependencies if cache does not exist
-#       #----------------------------------------------
-#       - name: Install dependencies
-#         run: pip install coverage
-
-#       - name: download coverage files
-#         uses: actions/download-artifact@v3
-#         with:
-#           name: coverage
-#           path: coverage
-
-#       - name: convert coverage to xml
-#         run: |
-#           coverage combine --data-file=coverage/.coverage
-#           coverage xml -i --data-file=coverage/.coverage
-#           ls
-#           ls coverage
-
-#       - name: Upload coverage to Codecov
-#         uses: codecov/codecov-action@v3
-#         with:
-#           token: ${{ secrets.CODECOV_TOKEN }}
-#           # directory: ./coverage
-#           # env_vars: OS,PYTHON
-#           fail_ci_if_error: false
-#           # files: ./coverage/coverage.xml
-#           # flags: unittests
-#           # name: codecov-umbrella
-#           verbose: true
+     
+      #----------------------------------------------
+      # Run tests and upload coverage
+      #----------------------------------------------
+      - name: Run tests for coverage
+        run: make test-w-coverage
+
+      - name: copy coverage
+        run: |
+          mkdir coverage
+          cp -v .coverage coverage/.coverage.${{ matrix.os }}-py${{ matrix.python-version }}
+
+      - name: store coverage files
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage
+          path: coverage
+
+
+  upload-coverage:
+    name: Upload test coverage to CodeCov
+    needs: [coverage]
+    runs-on: ubuntu-latest
+    permissions:
+      statuses: write
+    steps:
+      #----------------------------------------------
+      #       check-out repo and set-up python
+      #----------------------------------------------
+      - name: Check out repository
+        uses: actions/checkout@v4
+      - name: Set up python ${{ env.MINIMUM_PYTHON_VERSION }}
+        id: setup-python
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ env.MINIMUM_PYTHON_VERSION }}
+
+      #----------------------------------------------
+      # install dependencies if cache does not exist
+      #----------------------------------------------
+      - name: Install dependencies
+        run: pip install coverage
+
+      - name: download coverage files
+        uses: actions/download-artifact@v4
+        with:
+          name: coverage
+          path: coverage
+
+      - name: convert coverage to xml
+        run: |
+          coverage combine --data-file=coverage/.coverage
+          coverage xml -i --data-file=coverage/.coverage
+          ls
+          ls coverage
+
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v3
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          # directory: ./coverage
+          # env_vars: OS,PYTHON
+          fail_ci_if_error: false
+          # files: ./coverage/coverage.xml
+          # flags: unittests
+          # name: codecov-umbrella
+          verbose: true
 
    # https://github.com/marketplace/actions/alls-green#why used for branch protection checks
   check:
     if: always()
-    needs: [lint]
+    needs: [lint, coverage]
     runs-on: ubuntu-latest
     permissions: {}
     steps:
diff --git a/Makefile b/Makefile
index 8dde24f..a321129 100644
--- a/Makefile
+++ b/Makefile
@@ -34,7 +34,7 @@ run-doc-tests:
 	${INVENV} python -m doctest -v karp_lex/value_objects/unique_id.py
 
 # run all tests with coverage collection
-run-all-tests-w-coverage:
+test-w-coverage:
 	${INVENV} pytest -vv --cov=src/${PROJECT}  --cov-report=xml tests
 
 # check types
diff --git a/pyproject.toml b/pyproject.toml
index d85e505..113a2f4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -12,7 +12,7 @@ dependencies = [
 ]
 license = "MIT"
 readme = "README.md"
-requires-python = ">= 3.8"
+requires-python = ">= 3.9"
 classifiers = [
     "Development Status :: 4 - Beta",
     # "Development Status :: 5 - Production/Stable",
@@ -64,3 +64,12 @@ allow-direct-references = true
 
 [tool.black]
 target-version = ["py38", "py39", "py310", "py311", "py312"]
+
+[tool.hatch.envs.test]
+dependencies = ["pytest", "pytest-cov"]
+
+# [tool.hatch.envs.test.scripts]
+# run = "pytest tests"
+
+[[tool.hatch.envs.test.matrix]]
+python = ["3.8", "3.9", "3.10", "3.11", "3.12"]