tweak a test for new pandas behaviour

Author: robertjwilson

tests/test_api_lazy.py

@@ -3,6 +3,7 @@
 import glob
 import xarray as xr
 import os, pytest
+import numpy as np
 
 nc.options(lazy=True)
 
@@ -45,7 +46,7 @@ def test_errors(self):
         assert tracker.contents.long_name[0] == 'Monthly Means of Global Sea Surface Temperature'
         tracker.assign(sst2 = lambda x: x.sst + 283)
         tracker.run()
-        assert tracker.contents.long_name[1] == None
+        assert str(tracker.contents.long_name[1]) == "nan" 
 
 
         # check wildcard