debugdirstate: add command to rebuildstate test to modify dirstate

Debugging the dirstate helps if you have options to add files for normal lookup
or drop them from the dirstate. This patch adds a convenience command to
test-rebuilddirstate.t to modify the dirstate. It will be used in the next patch
to write proper tests for debugrebuilddirstate --minimal

tests/test-rebuildstate.t

@@ -1,30 +1,70 b''
+
+  $ cat > adddrop.py <<EOF
+  > from mercurial import cmdutil
+  > cmdtable = {}
+  > command = cmdutil.command(cmdtable)
+  > @command('debugadddrop',
+  >   [('', 'drop', False, 'drop file from dirstate', 'FILE'),
+  >    ('', 'normal-lookup', False, 'add file to dirstate', 'FILE')],
+  >     'hg debugadddrop')
+  > def debugadddrop(ui, repo, *pats, **opts):
+  >   '''Add or drop unnamed arguments to or from the dirstate'''
+  >   drop = opts.get('drop')
+  >   nl = opts.get('normal_lookup')
+  >   if nl and drop:
+  >       raise error.Abort('drop and normal-lookup are mutually exclusive')
+  >   wlock = repo.wlock()
+  >   try:
+  >     for file in pats:
+  >       if opts.get('normal_lookup'):
+  >         repo.dirstate.normallookup(file)
+  >       else:
+  >         repo.dirstate.drop(file)
+  > 
+  >     repo.dirstate.write(repo.currenttransaction())
+  >   finally:
+  >     wlock.release()
+  > EOF
+
+  $ echo "[extensions]" >> $HGRCPATH
+  $ echo "debugadddrop=`pwd`/adddrop.py" >> $HGRCPATH
+
 basic test for hg debugrebuildstate
 
   $ hg init repo
   $ cd repo
 
   $ touch foo bar
   $ hg ci -Am 'add foo bar'
   adding bar
   adding foo
 
   $ touch baz
   $ hg add baz
   $ hg rm bar
 
   $ hg debugrebuildstate
 
 state dump after
 
   $ hg debugstate --nodates | sort
   n 644         -1 set                 bar
   n 644         -1 set                 foo
 
+  $ hg debugadddrop --normal-lookup file1 file2
+  $ hg debugadddrop --drop bar
+  $ hg debugadddrop --drop
+  $ hg debugstate --nodates
+  n   0         -1 unset               file1
+  n   0         -1 unset               file2
+  n 644         -1 set                 foo
+  $ hg debugrebuildstate
+
 status
 
   $ hg st -A
   ! bar
   ? baz
   C foo
 
   $ cd ..