diff --git a/test/test_option_validator.py b/test/test_option_validator.py
index c26e5f6..f2ccd8b 100644
--- a/test/test_option_validator.py
+++ b/test/test_option_validator.py
@@ -108,3 +108,9 @@ def test_validator_warning_master_slave():
     cfg.ip_admin_eth0.ip_admin_eth0 = ['val']
     assert cfg.ip_admin_eth0.ip_admin_eth0 == ['val']
     assert cfg.cfgimpl_get_values().get_last_warning() == 'invalid value val for option ip_admin_eth0: error'
+    cfg.ip_admin_eth0.ip_admin_eth0 = ['val', 'val1', 'val1']
+    assert cfg.cfgimpl_get_values().get_last_warning() == 'invalid value val for option ip_admin_eth0: error'
+    cfg.ip_admin_eth0.ip_admin_eth0 = ['val1', 'val', 'val1']
+    assert cfg.cfgimpl_get_values().get_last_warning() == 'invalid value val for option ip_admin_eth0: error'
+    cfg.ip_admin_eth0.ip_admin_eth0 = ['val1', 'val1', 'val']
+    assert cfg.cfgimpl_get_values().get_last_warning() == 'invalid value val for option ip_admin_eth0: error'