tests/test-dispatch.t

tests: add script to disable a selected wire protocol capability

This can be used to test that the client and server both fall back to the
previous wire protocol when the capability is not supported.

It is currently used by test-push-http.t and I plan to use it for the HTTP
long argument support tests.

test command parsing and dispatch

  $ "$TESTDIR/hghave" no-outer-repo || exit 80

  $ dir=`pwd`

  $ hg init a
  $ cd a
  $ echo a > a
  $ hg ci -Ama
  adding a

Missing arg:

  $ hg cat
  hg cat: invalid arguments
  hg cat [OPTION]... FILE...
  
  output the current or given revision of files
  
  options:
  
   -o --output FORMAT        print output to file with formatted name
   -r --rev REV              print the given revision
      --decode               apply any matching decode filter
   -I --include PATTERN [+]  include names matching the given patterns
   -X --exclude PATTERN [+]  exclude names matching the given patterns
  
  [+] marked option can be specified multiple times
  
  use "hg help cat" to show the full help text
  [255]

[defaults]

  $ hg cat a
  a
  $ cat >> $HGRCPATH <<EOF
  > [defaults]
  > cat = -r null
  > EOF
  $ hg cat a
  a: no such file in rev 000000000000
  [1]

No repo:

  $ cd $dir
  $ hg cat
  abort: no repository found in '$TESTTMP' (.hg not found)!
  [255]