diff --git a/0004-general-uri-scheme/data/test/uri-scheme-tester.sh b/0004-general-uri-scheme/data/test/uri-scheme-tester.sh
index 5616044..c0c3f94 100755
--- a/0004-general-uri-scheme/data/test/uri-scheme-tester.sh
+++ b/0004-general-uri-scheme/data/test/uri-scheme-tester.sh
@@ -13,16 +13,15 @@ if ! command -v yq > /dev/null; then
 fi
 
 readonly DATA="${1:-"$(git rev-parse --show-toplevel)/0004-general-uri-scheme/data"}"
+readonly TMP="$(mktemp -d)"
 
 readonly RAD_URI_NE="${DATA}/rad-uri.ne"
-readonly RAD_URI_JS="$TMPDIR/rad-uri.js"
+readonly RAD_URI_JS="${TMP}/rad-uri.js"
 
 if ! nearleyc -o "$RAD_URI_JS" "$RAD_URI_NE"; then
     exit 1
 fi
 
-readonly TMP="$(mktemp -d)"
-
 FAILED=0
 for EXPECTED in "${DATA}"/test/tc*-expected.json; do
     INPUT="${EXPECTED%-expected.json}"