diff --git a/tests/psub.in b/tests/psub.in
index 5a4808477..76d8787dc 100644
--- a/tests/psub.in
+++ b/tests/psub.in
@@ -12,6 +12,10 @@ rm $filename
 set -l filename (echo foo | psub --testing --fifo)
 test -p $filename
 or echo 'psub is not a fifo' >&2
+# hack: the background write that psub peforms may block
+# until someone opens the fifo for reading. So make sure we
+# actually read it.
+cat $filename > /dev/null
 rm $filename
 
 cat (echo foo | psub)