diff --git a/unittest/force-styles/tests/improper-distharm.yaml b/unittest/force-styles/tests/improper-distharm.yaml
index e2916d3d74..5a3f4e08a5 100644
--- a/unittest/force-styles/tests/improper-distharm.yaml
+++ b/unittest/force-styles/tests/improper-distharm.yaml
@@ -13,7 +13,9 @@ improper_style: distharm
 improper_coeff: ! |
   1  75.0 5.5
   2  45.0 6.2
-extract: ! ""
+extract: ! |
+  k 1
+  chi 1
 natoms: 29
 init_energy: 3973.601605432119
 init_stress: ! |2-