diff --git a/.github/workflows/on_push.yaml b/.github/workflows/on_push.yaml
index 945cad1..cce14e0 100644
--- a/.github/workflows/on_push.yaml
+++ b/.github/workflows/on_push.yaml
@@ -1,6 +1,8 @@
 name: Tests
 
 on:
+  pull_request:
+    branches: [ "master" ]
   push:
     branches:
       - master
diff --git a/test/test_deep/config/test_config_service.py b/test/test_deep/config/test_config_service.py
index a36f284..3d7ba48 100644
--- a/test/test_deep/config/test_config_service.py
+++ b/test/test_deep/config/test_config_service.py
@@ -25,6 +25,6 @@ def test_custom_attr_callable(self):
         self.assertEqual(service.SOME_VALUE, 'thing')
 
     def test_env_attr(self):
-        items_ = os.environ.get('PATH')
+        items_ = os.environ.setdefault("DEEP_PATH", "a thing")
         service = ConfigService({})
         self.assertEqual(service.PATH, items_)