tests/test-unified-test.t

templatekw: choose {latesttag} by len(changes), not date (issue5659)

As Augie reported in the bug, the current heuristic of choosing the
best tag of a merge commit by taking the one with newest tag (in terms
of tagging date) currently fails in the Mercurial repo itself. Copying
the example from Yuya:

  $ hg glog -T '{node|short} {latesttag}+{latesttagdistance}\n' \
    -r '4.2.3: & (merge() + parents(merge()) + tag())'
  o    02a745c20121 4.2.3+5
  |\
  | o    86aca74a063b 4.2.3+4
  | |\
  | | o  e6d8ee3c9ec3 4.3-rc+109
  | | |
  | | ~
  o |  a3ce07e2dde5 4.3.1+2
  : |
  o |  3fee7f7d2da0 4.3.1+0
  |/
  o    98e990bb7330 4.2.3+3
  |\
  | ~
  o  506d7e48fbe6 4.2.3+2
  :
  o  943c91326b23 4.2.3+0
  |
  ~

It seems to me like the best choice is the tag with the smallest
number of changes since it (across all paths, not the longest single
path). So that's what this patch does, even though it's
costly. Best-of-5 timings for Yuya's command above shows a slowdown
from 1.293s to 1.610s. We can optimize it later.

Differential Revision: https://phab.mercurial-scm.org/D447

Test that the syntax of "unified tests" is properly processed
==============================================================

Simple commands:

  $ echo foo
  foo
  $ printf 'oh no'
  oh no (no-eol)
  $ printf 'bar\nbaz\n' | cat
  bar
  baz

Multi-line command:

  $ foo() {
  >     echo bar
  > }
  $ foo
  bar

Return codes before inline python:

  $ sh -c 'exit 1'
  [1]

Doctest commands:

  >>> from __future__ import print_function
  >>> print('foo')
  foo
  $ echo interleaved
  interleaved
  >>> for c in 'xyz':
  ...     print(c)
  x
  y
  z
  >>> print()
  
  >>> foo = 'global name'
  >>> def func():
  ...     print(foo, 'should be visible in func()')
  >>> func()
  global name should be visible in func()
  >>> print('''multiline
  ... string''')
  multiline
  string

Regular expressions:

  $ echo foobarbaz
  foobar.* (re)
  $ echo barbazquux
  .*quux.* (re)

Globs:

  $ printf '* \\foobarbaz {10}\n'
  \* \\fo?bar* {10} (glob)

Literal match ending in " (re)":

  $ echo 'foo (re)'
  foo (re)

Windows: \r\n is handled like \n and can be escaped:

#if windows
  $ printf 'crlf\r\ncr\r\tcrlf\r\ncrlf\r\n'
  crlf
  cr\r (no-eol) (esc)
  \tcrlf (esc)
  crlf\r (esc)
#endif

Combining esc with other markups - and handling lines ending with \r instead of \n:

  $ printf 'foo/bar\r'
  fo?/bar\r (no-eol) (glob) (esc)
#if windows
  $ printf 'foo\\bar\r'
  foo/bar\r (no-eol) (glob) (esc)
#endif
  $ printf 'foo/bar\rfoo/bar\r'
  foo.bar\r \(no-eol\) (re) (esc)
  foo.bar\r \(no-eol\) (re)

testing hghave

  $ hghave true
  $ hghave false
  skipped: missing feature: nail clipper
  [1]
  $ hghave no-true
  skipped: system supports yak shaving
  [1]
  $ hghave no-false

Conditional sections based on hghave:

#if true
  $ echo tested
  tested
#else
  $ echo skipped
#endif

#if false
  $ echo skipped
#else
  $ echo tested
  tested
#endif

#if no-false
  $ echo tested
  tested
#else
  $ echo skipped
#endif

#if no-true
  $ echo skipped
#else
  $ echo tested
  tested
#endif

Exit code:

  $ (exit 1)
  [1]