tests/test-update-dest.t

sparse: move config file writing into core

The code was refactored during the move to be more procedural
instead of using string formatting. This has the benefit of not
writing empty sections, which changed tests.

Test update.requiredest
  $ cd $TESTTMP
  $ cat >> $HGRCPATH <<EOF
  > [commands]
  > update.requiredest = True
  > EOF
  $ hg init repo
  $ cd repo
  $ echo a >> a
  $ hg commit -qAm aa
  $ hg up
  abort: you must specify a destination
  (for example: hg update ".::")
  [255]
  $ hg up .
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ HGPLAIN=1 hg up
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --config commands.update.requiredest=False up
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd ..

Check update.requiredest interaction with pull --update
  $ hg clone repo clone
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd repo
  $ echo a >> a
  $ hg commit -qAm aa
  $ cd ../clone
  $ hg pull --update
  abort: update destination required by configuration
  (use hg pull followed by hg update DEST)
  [255]