diff --git a/test/test_scenario_4.py b/test/test_scenario_4.py
index b979b4003..2a99c8ffe 100644
--- a/test/test_scenario_4.py
+++ b/test/test_scenario_4.py
@@ -1,10 +1,12 @@
 import datetime 
 import os
 import pytest
+import xarray
 
 import numpy as np
+from pyproj import CRS
 
-from RAiDER.delay import tropo_delay
+from RAiDER.delay import tropo_delay, _get_delays_on_cube
 from RAiDER.llreader import RasterRDR
 from RAiDER.losreader import Zenith
 from RAiDER.processWM import prepareWeatherModel
@@ -36,4 +38,31 @@ def test_aoi_without_xpts():
     assert np.nanmean(zen_hydro) > 0
 
 
+def test_get_delays_on_cube():
 
+    los = Zenith()
+    latfile = os.path.join(SCENARIO_DIR, 'lat.rdr')
+    lonfile = os.path.join(SCENARIO_DIR, 'lon.rdr')
+    hgtfile = os.path.join(SCENARIO_DIR, 'hgt.rdr')
+    aoi = RasterRDR(latfile, lonfile, hgtfile)
+    dt = datetime.datetime(2020,1,1)
+
+    wm = ERA5()
+    wm.set_latlon_bounds(aoi.bounds())
+    wm.setTime(dt)
+    f = prepareWeatherModel(wm, dt, aoi.bounds())
+
+    with xarray.load_dataset(f) as ds:
+        wm_levels = ds.z.values
+        wm_proj = CRS.from_wkt(ds['proj'].attrs['crs_wkt'])
+    
+    zref = 10000
+
+    with pytest.raises(AttributeError):
+        aoi.xpts
+    
+    ds = _get_delays_on_cube(dt, f, wm_proj, aoi, wm_levels, los, wm_proj, zref)
+
+    assert len(ds.x) > 0
+    assert ds.hydro.mean() > 0
+    
diff --git a/tools/RAiDER/delay.py b/tools/RAiDER/delay.py
index e3175eb8d..4895abf23 100755
--- a/tools/RAiDER/delay.py
+++ b/tools/RAiDER/delay.py
@@ -86,8 +86,9 @@ def tropo_delay(
 
 
     #TODO: expose this as library function
-    ds = _get_delays_on_cube(dt, weather_model_file, wm_proj, aoi, height_levels,
-            los, crs, zref)
+    ds = _get_delays_on_cube(
+        dt, weather_model_file, wm_proj, aoi, height_levels, los, crs, zref
+    )
 
     if (aoi.type() == 'bounding_box') or (aoi.type() == 'Geocube'):
         return ds, None