diff --git a/bin/git-check-assertions b/bin/git-check-assertions
index 9e85abf..5501358 100755
--- a/bin/git-check-assertions
+++ b/bin/git-check-assertions
@@ -24,14 +24,6 @@
 
 set -euo pipefail
 
-assert_fails() {
-  ! "$@" || {
-    echo "Expected command to fail, but it succeeded."
-    exit 1
-  }
-}
-export -f assert_fails
-
 # helper functions inspired by bats/bats-assert
 run() {
   set +e