[PATCH 00/10] 'test_i18ngrep'-related fixes and improvements

When 'test_i18ngrep' can't find the expected pattern, it exits completely silently; when its negated form does find the pattern that shouldn't be there, it prints the matching line(s) but otherwise exits without any error message. This leaves the developer puzzled about what could have gone wrong. Well, at least it left me puzzled...

Initially all I wanted to do was to make 'test_i18ngrep' more informative on failure, but then skeletons started to fall out of the closet^Wour test suite, and BAM! before I knew it I had 10 patches:

  t5541: add 'test_i18ngrep's missing filename parameter
  t5812: add 'test_i18ngrep's missing filename parameter
  t6022: don't run 'git merge' upstream of a pipe
  t4001: don't run 'git status' upstream of a pipe

Bugfixes for a few tests.  The first two are fun.

  t5510: consolidate 'grep' and 'test_i18ngrep' patterns
  t5536: let 'test_i18ngrep' read the file without redirection

Cleanups.

  t: move 'test_i18ncmp' and 'test_i18ngrep' to 'test-lib-functions.sh'

Pure code movement.

  t: forbid piping into 'test_i18ngrep'
  t: make sure that 'test_i18ngrep' got enough parameters

These try to prevent similar bugs in our tests in the future. Both are imperfect, see the commit messages about their limitations and why I think they are good enough.

  t: make 'test_i18ngrep' more informative on failure

Again, see the commit message about its limitations and why it's good enough.

 t/t4001-diff-rename.sh        | 11 ++++++---
 t/t5510-fetch.sh              |  9 +++-----
 t/t5536-fetch-conflicts.sh    |  2 +-
 t/t5541-http-push-smart.sh    |  2 +-
 t/t5812-proto-disable-http.sh |  3 +--
 t/t6022-merge-rename.sh       |  6 +++--
 t/test-lib-functions.sh       | 53 +++++++++++++++++++++++++++++++++++++++++++
 t/test-lib.sh                 | 26 ---------------------
 8 files changed, 71 insertions(+), 41 deletions(-)