diff --git a/tests/test_dashboard_projects_endpoint.py b/tests/test_dashboard_projects_endpoint.py
index 23270d5..090c142 100644
--- a/tests/test_dashboard_projects_endpoint.py
+++ b/tests/test_dashboard_projects_endpoint.py
@@ -584,8 +584,10 @@ class TestPlanningEndpoints:
 
 
 class TestSseAuth:
-    def test_sse_stream_requires_cookie(self, stub):
-        # No Cookie header → handler short-circuits with 401.
+    def test_sse_stream_requires_cookie(self, stub, monkeypatch):
+        # Auth is off by default (tailnet-only); without it the stream opens
+        # and never returns. No Cookie header → handler short-circuits with 401.
+        monkeypatch.setenv("DASHBOARD_AUTH", "on")
         stub.path = "/api/projects/stream"
         stub.command = "GET"
         stub.handle_projects_stream()