diff --git a/tests/test_geoseries.py b/tests/test_geoseries.py
index 5137b38..ba5ed62 100644
--- a/tests/test_geoseries.py
+++ b/tests/test_geoseries.py
@@ -240,11 +240,10 @@ class TestSeries(unittest.TestCase):
             self.landmarks.to_crs(crs=None, epsg=None)
 
     def test_fillna(self):
-        na = self.na_none.fillna()
+        na = self.na_none.fillna(Point())
         self.assertTrue(isinstance(na[2], BaseGeometry))
         self.assertTrue(na[2].is_empty)
-        with self.assertRaises(NotImplementedError):
-            self.na_none.fillna(method='backfill')
+        self.na_none.fillna(method='backfill')
         
     def test_interpolate(self):
         res = self.g5.interpolate(0.75, normalized=True)