Remember what branches we delete and do not try to reparent them in cleanup.

tests/git_rebase_update_test.py

 #!/usr/bin/env python
 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Unit tests for git_rebase_update.py"""
 
 import os
 import sys
 
@@ skipping 98 matching lines @@
     """)
     self.assertEquals(self.repo['A'], self.origin['A'])
     self.assertEquals(self.repo['E'], self.origin['E'])
 
     with self.repo.open('bob', 'wb') as f:
       f.write('testing auto-freeze/thaw')
 
     output, _ = self.repo.capture_stdio(self.reup.main)
     self.assertIn('Cannot rebase-update', output)
 
+    self.repo.run(self.nb.main, ['empty_branch'])
+    self.repo.run(self.nb.main, ['--upstream_current', 'empty_branch2'])
+
     self.repo.git('checkout', 'branch_K')
 
     output, _ = self.repo.capture_stdio(self.reup.main)
 
     self.assertIn('Rebasing: branch_G', output)
     self.assertIn('Rebasing: branch_K', output)
     self.assertIn('Rebasing: branch_L', output)
     self.assertIn('Rebasing: foobar', output)
     self.assertIn('Rebasing: sub_K', output)
     self.assertIn('Deleted branch branch_G', output)
+    self.assertIn('Deleted branch empty_branch', output)
+    self.assertIn('Deleted branch empty_branch2', output)

[agable, 2014/03/29 00:02:04]

See today's ToT: Would be better to have many smaller tests of rebase-update
that each test one feature of it (deleting empty branches, reparenting children
of deleted branches, etc.)

     self.assertIn('Reparented branch_K to track origin/master', output)
 
     self.assertSchema("""
     A B C D E F G M N O H I J K sub_K
                               K L
                       O foobar1 foobar2
     A old_file
     """)
 
     output, _ = self.repo.capture_stdio(self.reup.main)
@@ skipping 189 matching lines @@
     """)
 
 
 if __name__ == '__main__':
   sys.exit(coverage_utils.covered_main((
     os.path.join(DEPOT_TOOLS_ROOT, 'git_rebase_update.py'),
     os.path.join(DEPOT_TOOLS_ROOT, 'git_new_branch.py'),
     os.path.join(DEPOT_TOOLS_ROOT, 'git_reparent_branch.py'),
     os.path.join(DEPOT_TOOLS_ROOT, 'git_rename_branch.py')
   )))