diff --git a/tests/test_publication.py b/tests/test_publication.py
index 3e98c47..571a079 100644
--- a/tests/test_publication.py
+++ b/tests/test_publication.py
@@ -71,6 +71,15 @@ review_interval: 6m
 
 
 class PublicationTest(unittest.TestCase):
+    def setUp(self) -> None:
+        self.source_root_env = mock.patch.dict(
+            os.environ, {"POLICY_NEXUS_SOURCE_ROOT": ""}, clear=False
+        )
+        self.source_root_env.start()
+
+    def tearDown(self) -> None:
+        self.source_root_env.stop()
+
     def test_archive_build_accepts_only_exact_source_revision_override(self) -> None:
         with tempfile.TemporaryDirectory() as directory:
             root = Path(directory)