tests/test-cat.t

obsolescence: add test case D-1 for obsolescence markers exchange

About 3 years ago, in August 2014, the logic to select what markers to select on
push was ported from the evolve extension to Mercurial core. However, for some
unclear reasons, the tests for that logic were not ported alongside.
I realised it a couple of weeks ago while working on another push related issue.
I've made a clean up pass on the tests and they are now ready to integrate the
core test suite. This series of changesets do not change any logic. I just adds
test for logic that has been around for about 10 versions of Mercurial.

They are a patch for each test case. It makes it easier to review and postpone
one with documentation issues without rejecting the wholes series.

This patch introduce case D-1:

    Pruned changeset based on missing precursor of something not present

Each test case comes it in own test file. It help parallelism and does not
introduce a significant overhead from having a single unified giant test file.
Here are timing  to support this claim.

# Multiple test files version:
# run-tests.py --local -j 1 test-exchange-*.t
53.40s user 6.82s system 85% cpu 1:10.76 total
52.79s user 6.97s system 85% cpu 1:09.97 total
52.94s user 6.82s system 85% cpu 1:09.69 total

# Single test file version:
# run-tests.py --local -j 1 test-exchange-obsmarkers.t
52.97s user 6.85s system 85% cpu 1:10.10 total
52.64s user 6.79s system 85% cpu 1:09.63 total
53.70s user 7.00s system 85% cpu 1:11.17 total

  $ hg init
  $ echo 0 > a
  $ echo 0 > b
  $ hg ci -A -m m
  adding a
  adding b
  $ hg rm a
  $ hg cat a
  0
  $ hg cat --decode a # more tests in test-encode
  0
  $ echo 1 > b
  $ hg ci -m m
  $ echo 2 > b
  $ hg cat -r 0 a
  0
  $ hg cat -r 0 b
  0
  $ hg cat -r 1 a
  a: no such file in rev 7040230c159c
  [1]
  $ hg cat -r 1 b
  1

Test multiple files

  $ echo 3 > c
  $ hg ci -Am addmore c
  $ hg cat b c
  1
  3
  $ hg cat .
  1
  3
  $ hg cat . c
  1
  3

Test fileset

  $ hg cat 'set:not(b) or a'
  3
  $ hg cat 'set:c or b'
  1
  3

  $ mkdir tmp
  $ hg cat --output tmp/HH_%H c
  $ hg cat --output tmp/RR_%R c
  $ hg cat --output tmp/h_%h c
  $ hg cat --output tmp/r_%r c
  $ hg cat --output tmp/%s_s c
  $ hg cat --output tmp/%d%%_d c
  $ hg cat --output tmp/%p_p c
  $ hg log -r . --template "{rev}: {node|short}\n"
  2: 45116003780e
  $ find tmp -type f | sort
  tmp/.%_d
  tmp/HH_45116003780e3678b333fb2c99fa7d559c8457e9
  tmp/RR_2
  tmp/c_p
  tmp/c_s
  tmp/h_45116003780e
  tmp/r_2

Test working directory

  $ echo b-wdir > b
  $ hg cat -r 'wdir()' b
  b-wdir

Environment variables are not visible by default

  $ PATTERN='t4' hg log -r '.' -T "{ifcontains('PATTERN', envvars, 'yes', 'no')}\n"
  no

Environment variable visibility can be explicit

  $ PATTERN='t4' hg log -r '.' -T "{envvars % '{key} -> {value}\n'}" \
  >                 --config "experimental.exportableenviron=PATTERN"
  PATTERN -> t4