diff --git a/.github/workflows/pythonapp.yml b/.github/workflows/pythonapp.yml
index 1e6c6fa..0ec00e9 100644
--- a/.github/workflows/pythonapp.yml
+++ b/.github/workflows/pythonapp.yml
@@ -7,11 +7,13 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    name: Test on Python ${{ matrix.python-version }} and ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
     strategy:
-      max-parallel: 4
       matrix:
         python-version: [3.8, 3.7, 3.6, pypy3]
+        os: [ubuntu-latest, windows-latest, macOS-latest]
+
     steps:
     - uses: actions/checkout@v1
     - name: 'Set up Python ${{ matrix.python-version }}'
@@ -21,24 +23,20 @@ jobs:
 
     - name: 'Install package'
       run: |
-        make install-poetry
-        source $HOME/.poetry/env
+        pip3 install poetry
         make install
         pip3 install tox-gh-actions
 
     - name: 'List installed packages'
       run: |
-        source $HOME/.poetry/env
         poetry run pip freeze
 
     - name: 'List all tox test environments'
       run: |
-        source $HOME/.poetry/env
         make tox-listenvs
 
     - name: 'Run pytest with tox'
       run: |
-        source $HOME/.poetry/env
         make tox
 
     - name: 'Upload coverage report'
@@ -48,5 +46,4 @@ jobs:
     - name: 'Run linters'
       if: matrix.python-version == '3.8'
       run: |
-        source $HOME/.poetry/env
         make lint