diff --git a/.github/workflows/python-package.yml b/.github/workflows/python-package.yml
index f622149..93f4707 100644
--- a/.github/workflows/python-package.yml
+++ b/.github/workflows/python-package.yml
@@ -15,8 +15,8 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
-        os: [ubuntu-latest, macOS-latest, windows-latest]
+        python-version: ["3.9"]
+        os: [ubuntu-latest]
       fail-fast: false
 
     steps:
@@ -27,7 +27,7 @@ jobs:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
-        pdm sync -d -G test
+        pdm install -dG test
     - name: Run Tests
       run: |
         pytest -rsxXf --doctest-modules src tests