diff --git a/simpegPF/Tests/test_forward_PFproblem.py b/simpegPF/Tests/test_forward_PFproblem.py
index 09e2c30d..5f7d13a5 100644
--- a/simpegPF/Tests/test_forward_PFproblem.py
+++ b/simpegPF/Tests/test_forward_PFproblem.py
@@ -20,7 +20,7 @@ class MagFwdProblemTests(unittest.TestCase):
         sph_ind = PF.MagAnalytics.spheremodel(M, 0., 0., 0., 100)
         chi[sph_ind] = chiblk
         model = PF.BaseMag.BaseMagMap(M)
-        prob = PF.Magnetics.MagneticsDiffSecondary(M, mapping=model)
+        prob = PF.Magnetics.Problem3D_DiffSecondary(M, mapping=model)
         self.prob = prob
         self.M = M
         self.chi = chi