1 adding a

     2 1 files updated, 0 files merged, 0 files removed, 0 files unresolved

     3 1 files updated, 0 files merged, 0 files removed, 0 files unresolved

     4 1 files updated, 0 files merged, 0 files removed, 0 files unresolved

     5 % should fail because not at a head

     6 abort: repo has 3 heads - please merge with an explicit rev

     7 1 files updated, 0 files merged, 0 files removed, 0 files unresolved

     8 % should fail because > 2 heads

     9 abort: repo has 3 heads - please merge with an explicit rev

    10 % should succeed

    11 0 files updated, 0 files merged, 0 files removed, 0 files unresolved

    12 (branch merge, don't forget to commit)

    13 % should succeed - 2 heads

    14 0 files updated, 0 files merged, 0 files removed, 0 files unresolved

    15 (branch merge, don't forget to commit)

    16 % should fail because 1 head

    17 abort: there is nothing to merge - use "hg update" instead