tests/test-resolve

prepush: add more precise error messages

Part of the patch is from [e-mail]

- indicate the branch name where there are multiple heads
- give better advice when hitting a possible race, where new heads are added
  between discovery and the call to branchmap(). In that case, asking the user
  to merge isn't helpful, since only remote has the changes.

#!/bin/sh

# test that a commit clears the merge state.

hg init repo
cd repo

echo foo > file
hg commit -Am 'add file'

echo bar >> file
hg commit -Am 'append bar'

echo % create a second head
hg up -C 0
echo baz >> file
hg commit -Am 'append baz'

echo % failing merge
HGMERGE=internal:fail hg merge

echo resolved > file
hg resolve -m file
hg commit -m 'resolved'

echo % resolve -l, should be empty
hg resolve -l