diff --git a/seminar/tests_treelib.py b/seminar/tests_treelib.py
index 9c67ca22..3245d0a6 100644
--- a/seminar/tests_treelib.py
+++ b/seminar/tests_treelib.py
@@ -25,8 +25,16 @@ class SimpleTreeLibTests(TestCase):
 		self.root.save()
 	
 	def test_safe_functions(self):
+		# safe_pred
 		self.assertEqual(tl.safe_pred(self.other_node), self.some_node)
 		self.assertIsNone(tl.safe_pred(self.root))
 		self.assertIsNone(tl.safe_pred(self.some_node))
 		self.assertIsNone(tl.safe_pred(self.some_orphan))
 		self.assertIsNone(tl.safe_pred(self.other_orphan))
+
+		# safe_father_of_first
+		self.assertIsNone(tl.safe_father_of_first(self.root))
+		self.assertEqual(tl.safe_father_of_first(self.some_node), self.root)
+		self.assertEqual(tl.safe_father_of_first(self.other_node), self.root)
+		self.assertIsNone(tl.safe_father_of_first(self.some_orphan))
+		self.assertEqual(tl.safe_father_of_first(self.other_orphan), self.some_orphan)