diff --git a/tests/unit/java/com/android/server/connectivityservice/CSBlockedReasonsTest.kt b/tests/unit/java/com/android/server/connectivityservice/CSBlockedReasonsTest.kt
index 0590fbb..3ad8de8 100644
--- a/tests/unit/java/com/android/server/connectivityservice/CSBlockedReasonsTest.kt
+++ b/tests/unit/java/com/android/server/connectivityservice/CSBlockedReasonsTest.kt
@@ -387,6 +387,10 @@
                     BLOCKED_REASON_NETWORK_RESTRICTED or BLOCKED_REASON_APP_BACKGROUND
             )
         }
+        // waitForIdle since stubbing bpfNetMaps while CS handler thread calls
+        // bpfNetMaps.getNetPermForUid throws exception.
+        // ConnectivityService might haven't finished checking blocked status for all requests.
+        waitForIdle()
 
         // Disable background firewall chain
         doReturn(BLOCKED_REASON_NONE)