diff --git a/tests/spec/Extend_preprocess.ml b/tests/spec/Extend_preprocess.ml
index a81bc3b7ce89960961445c1c4151127b78d7428b..51e60d554404dca8e533abfada8cadc183efc44c 100644
--- a/tests/spec/Extend_preprocess.ml
+++ b/tests/spec/Extend_preprocess.ml
@@ -9,7 +9,7 @@ open Logic_const
    - global:          gl
   replaces node "must_replace(x)" with "<kind>_ok(x)". The typing phase
   validates that we find the right "<kind>_ok" for each kind of extension:
-   - if a must_replaced is found, it fails,
+   - if a must_replace is found, it fails,
    - if the wrong kind is found, a "\false" is generated
    - if everything is ok "\true" is generated
 *)