Ensure that writes to /dev/tty succeed to determine if it is writeable.

diff --git a/test/pick/test-pick b/test/pick/test-pick
index 08772bf..9b737ce 100755 (executable)
--- a/test/pick/test-pick
+++ b/test/pick/test-pick
@@ -98,7 +98,7 @@ cat >$expected <<EOF
 EOF
 check $expected $actual
 
-if test -w /dev/tty; then
+if test -w /dev/tty && printf '' >/dev/tty; then
   # Produce no standard output if no messages match and standard
   # output is a tty.  To test that even when run with stdout
   # detached, write directly to /dev/tty.  Can't capture the