[...]

  fn() {
    local NULLCMD=cat READNULLCMD=cat
    echo hello | >foo
    cat foo
    <bar
  }
  setopt shnullcmd
  print option set
  fn
  unsetopt shnullcmd
  print option unset
  fn
  rm -f foo bar
Was testing: SH_NULLCMD option
./E01options.ztst: test failed.
./E02xtrace.ztst: starting.
./E02xtrace.ztst: all tests successful.
./V01zmodload.ztst: starting.
./V01zmodload.ztst: all tests successful.
./V02zregexparse.ztst: starting.
./V02zregexparse.ztst: all tests successful.
./V03mathfunc.ztst: starting.
./V03mathfunc.ztst: all tests successful.
./V04features.ztst: starting.
./V04features.ztst: all tests successful.
./V05styles.ztst: starting.
./V05styles.ztst: all tests successful.
./V06parameter.ztst: starting.
./V06parameter.ztst: all tests successful.
./V07pcre.ztst: starting.
Testing PCRE multibyte with locale en_US.UTF-8
./V07pcre.ztst: all tests successful.
**************************************
35 successful test scripts, 1 failure, 0 skipped
**************************************
make[1]: *** [check] Error 1
make[1]: Leaving directory `/home/users/builder/rpm/BUILD/zsh-5.0.2/Test'
make: *** [test] Error 2
error: Bad exit status from /tmp/B.f6cdd5/rpm-tmp.3808 (%build)
RPM build errors:
    Bad exit status from /tmp/B.f6cdd5/rpm-tmp.3808 (%build)
ended at: Wed Jul  8 16:56:57 2015, done in 01days 00h 03m 01s
error: No files produced.
mesg: ttyname failed: Inappropriate ioctl for device
Begin-PLD-Builder-Info
Build-Time: user:122.40s sys:66.43s real:199.99s (faults io:15 non-io:5448317)
End-PLD-Builder-Info