diff --git a/unittest/force-styles/tests/bond-morse.yaml b/unittest/force-styles/tests/bond-morse.yaml
index d17e1db97e..f56662efd6 100644
--- a/unittest/force-styles/tests/bond-morse.yaml
+++ b/unittest/force-styles/tests/bond-morse.yaml
@@ -18,6 +18,8 @@ bond_coeff: ! |
   5 7000.0 0.3 1.0
 equilibrium: 5 1.5 1.1 1.3 1.2 1
 extract: ! |
+  d0 1
+  alpha 1
   r0 1
 natoms: 29
 init_energy: 5.607154540709207