diff --git a/tests/test_extrapolation.py b/tests/test_extrapolation.py
index c8d2f91c0cc0421de7ccc7d40b3f47ad4d3f93f9..fde327c2cd768581755185373ece8f8090f1f038 100644
--- a/tests/test_extrapolation.py
+++ b/tests/test_extrapolation.py
@@ -9,12 +9,13 @@ import gext.grassmann
 import utils
 
 SMALL = 1e-10
-THRESHOLD = 1e-2
+THRESHOLD = 2e-2
 
 @pytest.mark.parametrize("datafile", ["urea.json", "glucose.json"])
 @pytest.mark.parametrize("fitting", ["leastsquare", "qtr"])
 @pytest.mark.parametrize("regularization", [0.0, 1e-6, 5e-6])
-def test_extrapolation(datafile, fitting, regularization):
+@pytest.mark.parametrize("descriptor", ["distance", "coulomb"])
+def test_extrapolation(datafile, fitting, regularization, descriptor):
 
     # load test data from json file
     data = utils.load_json(f"tests/{datafile}")
@@ -29,7 +30,8 @@ def test_extrapolation(datafile, fitting, regularization):
 
     # initialize an extrapolator
     extrapolator = gext.Extrapolator(nelectrons, nbasis, natoms,
-        nsteps=n, fitting=fitting, fitting_regularization=regularization)
+        nsteps=n, fitting=fitting, fitting_regularization=regularization,
+        descriptor=descriptor)
 
     # load data in the extrapolator up to index n - 1
     for (coords, coeff, overlap) in zip(data["trajectory"][:n],