Index: wflow-py/wflow/wf_netcdfio.py
===================================================================
diff -u -re71ad2de03777dca02510a47f65dd6f7075a876b -r679be96f270311b53a1c4acd28f8226c34276e31
--- wflow-py/wflow/wf_netcdfio.py	(.../wf_netcdfio.py)	(revision e71ad2de03777dca02510a47f65dd6f7075a876b)
+++ wflow-py/wflow/wf_netcdfio.py	(.../wf_netcdfio.py)	(revision 679be96f270311b53a1c4acd28f8226c34276e31)
@@ -109,7 +109,7 @@
     res = srs.ImportFromEPSG(int(EPSG[5:]))
     if res != 0:
         logger.error("EPGS not converted correctly: " + EPSG + ". Is the GDAL_DATA environment variable set correctly?")
-        exit(1)
+        sys.exit(1)
 
     projStr = srs.ExportToProj4()
     proj_src = '+proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs'
@@ -448,8 +448,9 @@
         if os.path.exists(netcdffile):
             self.dataset = netCDF4.Dataset(netcdffile, mode='r')
         else:
-            logging.error(os.path.abspath(netcdffile) + " not found!")
-            exit(ValueError)
+            msg = os.path.abspath(netcdffile) + " not found!"
+            logging.error(msg)
+            raise ValueError(msg)
 
         logging.info("Reading input from netCDF file: " + netcdffile)
         self.alldat = {}
@@ -610,8 +611,9 @@
         if os.path.exists(netcdffile):
             self.dataset = netCDF4.Dataset(netcdffile, mode='r')
         else:
-            logging.error(os.path.abspath(netcdffile) + " not found!")
-            exit(ValueError)
+            msg = os.path.abspath(netcdffile) + " not found!"
+            logging.error(msg)
+            raise ValueError(msg)
 
         logging.info("Reading state input from netCDF file: " + netcdffile)
         self.alldat = {}
@@ -731,8 +733,9 @@
         if os.path.exists(netcdffile):
             self.dataset = netCDF4.Dataset(netcdffile, mode='r')
         else:
-            logging.error(os.path.abspath(netcdffile) + " not found!")
-            exit(ValueError)
+            msg = os.path.abspath(netcdffile) + " not found!"
+            logging.error(msg)
+            raise ValueError(msg)
 
 
         try: