diff --git a/nansat/tests/test_nsr.py b/nansat/tests/test_nsr.py
index 293d97a7..9303c8ef 100644
--- a/nansat/tests/test_nsr.py
+++ b/nansat/tests/test_nsr.py
@@ -28,7 +28,7 @@ def test_init_from_none(self):
         nsr = NSR(None)
 
         self.assertEqual(type(nsr), NSR)
-        self.assertEqual(nsr.Validate(), 5)
+        self.assertRaises(RuntimeError, nsr.Validate)
 
     def test_init_from_0(self):
         nsr = NSR(0)