diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 30f3c436..c562bcd8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -58,7 +58,7 @@ jobs:
     strategy:
       matrix:
         pyver: [3.6, 3.7, 3.8, 3.9]
-        os: [ubuntu, macos]
+        os: [ubuntu, macos, windows]
         #include:
         #  - pyver: pypy3
         #    os: ubuntu
@@ -88,12 +88,13 @@ jobs:
         path: requirements-dev.txt
     - name: Install JS dependencies
       run: grablib
+      env:
+        PYTHONIOENCODING: 'utf-8'
     - name: Run unittests
+      run: pytest
       env:
         COLOR: 'yes'
-      run: |
-        pytest
-        python -m coverage xml
+    - run: python -m coverage xml
     - name: Upload coverage
       uses: codecov/codecov-action@v1
       with:
diff --git a/setup.cfg b/setup.cfg
index 662e897c..7c89265c 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -4,6 +4,7 @@ markers = boxed: mark tests as boxed
 testpaths = tests/
 filterwarnings =
     error
+    ignore:The loop argument is deprecated:DeprecationWarning:asyncio.base_events
 xfail_strict = true
 
 [flake8]
diff --git a/tests/test_runserver_main.py b/tests/test_runserver_main.py
index f9c93b19..00f31ef7 100644
--- a/tests/test_runserver_main.py
+++ b/tests/test_runserver_main.py
@@ -134,10 +134,10 @@ async def test_aux_app(tmpworkdir, aiohttp_client):
         'test.txt': 'test value',
     })
     app = create_auxiliary_app(static_path='.')
-    cli = await aiohttp_client(app)
-    r = await cli.get('/test.txt')
-    assert r.status == 200
-    text = await r.text()
+    async with await aiohttp_client(app) as cli:
+        async with cli.get('/test.txt') as r:
+            assert r.status == 200
+            text = await r.text()
     assert text == 'test value'