Re: [PATCH v2] diff --shortstat --dirstat: remove duplicate output

On Mon, Mar 02, 2015 at 02:00:09AM +0100, SZEDER Gábor wrote:

It's not just 'grep -c' but the 'test' checking its output as well.

If something goes wrong and the line count doesn't match expectations
'test' fails silently leaving the developer clueless as to what went
wrong.

'test_line_count', on the other hand, produces useful output in case
of a failure:

   $ printf 'foo\nbar\n' >actual
   $ test_line_count = 1 actual
   test_line_count: line count for actual != 1
   foo
   bar

Since we have test_line_count, I think it makes sense to use it. But for
reference, I recently introduced the `verbose` function to test-lib.sh,
which lets you write:

  $ verbose test 1 = 2
  command failed:  'test' '1' '=' '2'

You can use it with any command that might fail without printing a
useful error message. The big downside is that it sees only the
arguments to the command, so if you write:

  $ test "$(do_something)" = 123

you will only see:

  command failed:  'test '456' '=' '123'

with no notion that $(do_something) was involved. So purpose-built
helpers like test_line_count will produce better output.

You may also be introduced in the "-x" option I recently introduced,
which can help with "quiet" failures. E.g.:

  $ ./t0001-init.sh -x --verbose-only=15
  [...]
  ok 13 - GIT_DIR & GIT_WORK_TREE (2)
  ok 14 - reinit
  
  expecting success: 
          mkdir template-source &&
          echo content >template-source/file &&
          git init --template=../template-source template-custom &&
          test_cmp template-source/file template-custom/.git/file
  
  + mkdir template-source
  + echo content
  + git init --template=../template-source template-custom
  Initialized empty Git repository in /home/peff/compile/git/t/trash directory.t0001-init/template-custom/.git/
  + test_cmp template-source/file template-custom/.git/file
  + diff -u template-source/file template-custom/.git/file
  ok 15 - init with --template
  ok 16 - init with --template (blank)

(ok, it's not that interesting because the test didn't fail, but
hopefully you get the point).

Now I'll stop hijacking your thread to advertise random test-lib
features. :)

-Peff