diff --git a/run_tests.sh b/run_tests.sh
index 2efcd5f..530661b 100755
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -1,6 +1,7 @@
 #!/bin/bash
 
 RESULTS=${RESULTS:-.}
+ID=0
 
 if [ -z "${FORMAT}" ] ; then
 	FORMAT=TAP
@@ -16,10 +17,20 @@ esac
 mkdir -p "${RESULTS}"/reports
 rm -rf "${RESULTS}"/reports/*
 
+# unique id across files
+# See TT#4590
+function fix_id() {
+	(( ID += 1))
+	local tmp_id
+	tmp_id=$(printf "%05d\n" "$ID")
+	sed -i "s/id=\"00001\"/id=\"$tmp_id\"/" "$1"
+}
+
 function  do_test() {
-	echo "testing $1 -> ${RESULTS}/reports/${1}.${EXT}"
+	local RES="${RESULTS}/reports/${1}.${EXT}"
+	echo "testing $1 -> ${RES}"
 	if ${OUT_FORCE} ; then
-		cat<<EOF|lua5.1 - > ${RESULTS}/reports/${1}.${EXT}
+		cat<<EOF |lua5.1 - > "${RES}"
 EXPORT_ASSERT_TO_GLOBALS = true
 require "tests/${1}"
 ---- Control test output:
@@ -29,23 +40,27 @@ lu:setVerbosity(1)
 lu:run()
 EOF
 	else
-		cat<<EOF|lua5.1 -
+		cat<<EOF |lua5.1 -
 EXPORT_ASSERT_TO_GLOBALS = true
 require "tests/${1}"
 ---- Control test output:
 local lu = LuaUnit
 lu:setOutputType('${FORMAT}')
-lu:setFname('${RESULTS}/reports/${1}.${EXT}')
+lu:setFname('${RES}')
 lu:setVerbosity(1)
 lu:run()
 EOF
+		if [[ "${FORMAT}" = "JUNIT" ]] ; then
+			fix_id "${RES}"
+		fi
 	fi
 }
 
+
 if [[ -n "$@" ]]; then
-	for i in $@; do
+	for i in "$@"; do
 		if [ ! -f "$i" ]; then
-			echo "No $f found"
+			echo "No $i found"
 		else
 			do_test "$(basename "$i" .lua)"
 		fi
@@ -53,6 +68,6 @@ if [[ -n "$@" ]]; then
 	exit 0
 fi
 
-for i in $(find tests -name '*.lua' ! -name test_\*) ; do
+find tests -name '*.lua' ! -name test_\*| while read -r i ; do
 	do_test "$(basename "$i" .lua)"
 done
diff --git a/t/testrunner b/t/testrunner
index afa9c1f..379bc29 100755
--- a/t/testrunner
+++ b/t/testrunner
@@ -17,6 +17,4 @@ else
   mkdir -p "${RESULTS}"
 fi
 
-source_path="$(pwd)"
-
 RESULTS=${RESULTS} FORMAT=JUNIT ./run_tests.sh