diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 5801527..a4911df 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -6,11 +6,15 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10", "3.11"]
+        os: [ubuntu-latest]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
+        include:
+          - os: ubuntu-20.04
+            python-version: "3.6"
 
     steps:
       - uses: actions/checkout@v3
@@ -22,7 +26,6 @@ jobs:
         run: |
           python -m pip install --upgrade pip
           python -m pip install pytest
-          python -m pip install -e .
       - name: Pytest
         run: |
-          pytest
+          PYTHONPATH="." pytest