diff --git a/tests/substituter.sh b/tests/substituter.sh
index 94ae264725..8985982c2d 100755
--- a/tests/substituter.sh
+++ b/tests/substituter.sh
@@ -17,6 +17,7 @@ if test $1 = "--query"; then
             echo "" # deriver
             echo 0 # nr of refs
             echo 0 # download size
+            echo 0 # nar size
         else
             echo "bad command $cmd"
             exit 1
diff --git a/tests/substituter2.sh b/tests/substituter2.sh
index 70f7d0943b..c56a1bc47b 100755
--- a/tests/substituter2.sh
+++ b/tests/substituter2.sh
@@ -16,6 +16,7 @@ if test $1 = "--query"; then
             echo "" # deriver
             echo 0 # nr of refs
             echo 0 # download size
+            echo 0 # nar size
         else
             echo "bad command $cmd"
             exit 1