diff --git a/tests/Makefile.am b/tests/Makefile.am
index 9e1d6a198..5ac01aca3 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -8,6 +8,7 @@ TESTS_ENVIRONMENT = TEST_ROOT=$(TEST_ROOT) \
   NIX_LOG_DIR=$(TEST_ROOT)/log \
   NIX_STATE_DIR=$(TEST_ROOT)/state \
   NIX_DB_DIR=$(TEST_ROOT)/db \
+  NIX_BUILD_HOOK= \
   TOP=$(shell pwd)/.. \
   SHARED=$(extra1) \
   $(SHELL) -e -x
diff --git a/tests/locking.sh b/tests/locking.sh
index ac515fcea..f89e1240b 100644
--- a/tests/locking.sh
+++ b/tests/locking.sh
@@ -2,7 +2,7 @@ storeExpr=$($TOP/src/nix-instantiate/nix-instantiate locking.nix)
 
 echo "store expr is $storeExpr"
 
-for i in $(seq 1 5); do
+for i in 1 2 3 4 5; do
     echo "WORKER $i"
     $TOP/src/nix-store/nix-store -rvvvvvB "$storeExpr" &
 done