diff --git a/.github/is-version-number-acceptable.sh b/.github/is-version-number-acceptable.sh
index 2ee4b5f..5648a31 100755
--- a/.github/is-version-number-acceptable.sh
+++ b/.github/is-version-number-acceptable.sh
@@ -10,7 +10,7 @@ if ! $(dirname "$BASH_SOURCE")/has-functional-changes.sh; then
     exit 0
 fi
 
-current_version=$(python setup.py --version)
+current_version=$(poetry version --short)
 
 if git rev-parse --verify --quiet $current_version; then
     echo "Version $current_version already exists in commit:"
diff --git a/.github/workflows/workflow.yml b/.github/workflows/workflow.yml
index 0f4b5a1..ed095e8 100644
--- a/.github/workflows/workflow.yml
+++ b/.github/workflows/workflow.yml
@@ -55,21 +55,26 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Install Poetry
-        run: pipx install poetry
+      - name: Install Tox
+        run: pipx install tox
 
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
           python-version: 3.9.20
-          cache: poetry
-          cache-dependency-path: poetry.lock
 
-      - name: Install dependencies
-        run: make install
+      - name: Restore tests
+        uses: actions/cache@v4
+        with:
+          path: |
+            Makefile
+            openfisca_extension_template/tests
+            poetry.lock
+            tox.ini
+          key: tests-${{ github.sha }}
 
       - name: Lint files
-        run: make lint
+        run: tox -r -e lint
 
   test:
     runs-on: ubuntu-22.04
@@ -94,12 +99,6 @@ jobs:
             tox.ini
           key: tests-${{ github.sha }}
 
-      - name: Restore build
-        uses: actions/cache@v4
-        with:
-          path: dist
-          key: build-${{ hashFiles('poetry.lock') }}-${{ github.sha }}
-
       - name: Run the test suite
         run: tox -r -e py39
 
diff --git a/Makefile b/Makefile
index 08a9652..94c43d1 100644
--- a/Makefile
+++ b/Makefile
@@ -31,5 +31,5 @@ lint: clean
 	black --check `git ls-files | grep "\.py$$"`
 	yamllint `git ls-files | grep "\.yaml$$"`
 
-test: clean lint
+test: clean
 	PYTEST_ADDOPTS="--import-mode importlib" openfisca test --country-package=openfisca_country_template --extensions=openfisca_extension_template openfisca_extension_template/tests
diff --git a/pyproject.toml b/pyproject.toml
index 6ad5d33..3a5e3bc 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -96,7 +96,7 @@ python_files = "**/*.py"
 
 [tool.tox]
 requires = [ "tox>=4.19" ]
-env_list = [ "py39", "py310", "py311" ]
+env_list = [ "py39", "py310", "py311", "lint" ]
 
 [tool.tox.env_run_base]
 allowlist_externals = [ "make" ]
@@ -110,3 +110,17 @@ commands_pre = [
     ],
 ]
 commands = [ [ "make", "test" ] ]
+
+[tool.tox.env.lint]
+allowlist_externals = [ "make" ]
+basepython = [ "py39" ]
+commands_pre = [
+    [
+        "pip",
+        "install",
+        "--find-links",
+        "dist",
+        "openfisca_extension_template",
+    ],
+]
+commands = [ [ "make", "lint" ] ]