diff --git a/.github/workflows/continous_integration.yml b/.github/workflows/continous_integration.yml
index b8d54f1..e4eece5 100644
--- a/.github/workflows/continous_integration.yml
+++ b/.github/workflows/continous_integration.yml
@@ -40,13 +40,21 @@ jobs:
           cache: 'pip'
           cache-dependency-path: setup.py
 
+      - uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cache/pip
+          key: ${{ runner.os }}-pip-${{ hashFiles('**/pyproject.toml') }}
+          restore-keys: |
+            ${{ runner.os }}-pip-${{ hashFiles('**/pyproject.toml') }}
+            ${{ runner.os }}-pip-
+
       - name: Install dependencies
         run: |
           sudo apt-get update
           sudo apt-get install -y ffmpeg
           python -m pip install --upgrade pip
-          pip install pytest pytest-runner pytest-rerunfailures coveralls freezegun
-          pip install -e .
+          pip install -e ".[dev]"
 
       - name: Run tests
         run: coverage run -m pytest -v -s
diff --git a/pyproject.toml b/pyproject.toml
index 04aae2b..da17af2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -55,8 +55,18 @@ dependencies = [
     'tables',
     'regions'
 ]
+
 dynamic = ["version"]
 
+[project.optional-dependencies]
+test = [
+    'pytest',
+    'pytest-runner',
+    'pytest-rerunfailures',
+    'coveralls',
+    'freezegun',
+]
+
 [project.scripts]
 gwemopt-run = "gwemopt.run:run"