test: Add test for no net permission

test/functional/p2p_permissions.py

@@ -42,6 +42,12 @@ class P2PPermissionsTests(BitcoinTestFramework):
             ["relay", "noban", "mempool"],
             True)
 
+        self.checkpermission(
+            # no permission (even with forcerelay)
+            ["-whitelist=@127.0.0.1", "-whitelistforcerelay=1"],
+            [],
+            False)
+
         self.checkpermission(
             # relay permission removed (no specific permissions)
             ["-whitelist=127.0.0.1", "-whitelistrelay=0"],