Fixed ash misdetection.

1 files changed, 4 insertions, 2 deletions

diff --git a/test_runner b/test_runner
index 1c43c4a..415cc8b 100755
--- a/test_runner
+++ b/test_runner
@@ -17,6 +17,8 @@
 #   shellcheck disable=SC1090,SC1091
 # expr may be antiquated, but it is the only solution in some cases.
 #   shellcheck disable=SC2003
+# $() are not fully portable (POSIX != portable).
+#   shellcheck disable=SC2006
 
 # Return if test_runner already loaded.
 [ -z "${RUNNER_LOADED:-}" ] || return 0
@@ -128,8 +130,8 @@ EOF
     shell_present=${FALSE}
     case ${shell} in
       ash)
-        shell_bin=`which busybox`
-        [ $? -eq "${TRUE}" ] && shell_present="${TRUE}"
+        shell_bin=`which busybox |grep -v '^no busybox'`
+        [ $? -eq "${TRUE}" -a -n "${shell_bin}" ] && shell_present="${TRUE}"
         shell_bin="${shell_bin} ash"
         shell_name=${shell}
         ;;