(command.CommandList
  children: [
    (command.Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (lhs_expr.LhsName name:test_description)
          op: Equal
          rhs: {(SQ <'test unique sha1 abbreviation on "index from..to" line'>)}
        )
      ]
    )
    (C {(.)} {(./test-lib.sh)})
    (command.SimpleCommand
      words: [{(cat)}]
      redirects: [
        (redir.Redir op:<Redir_Great '>'> fd:16777215 arg_word:{(expect_initial)})
        (redir.HereDoc
          op: <Redir_DLess '<<'>
          fd: 16777215
          here_begin: {(EOF)}
          here_end_span_id: 24
          stdin_parts: [('100644 blob 51d2738463ea4ca66f8691c91e33ce64b7d41bb1\tfoo\n')]
        )
      ]
    )
    (command.SimpleCommand
      words: [{(cat)}]
      redirects: [
        (redir.Redir op:<Redir_Great '>'> fd:16777215 arg_word:{(expect_update)})
        (redir.HereDoc
          op: <Redir_DLess '<<'>
          fd: 16777215
          here_begin: {(EOF)}
          here_end_span_id: 36
          stdin_parts: [('100644 blob 51d2738efb4ad8a1e40bed839ab8e116f0a15e47\tfoo\n')]
        )
      ]
    )
    (C {(test_expect_success)} {(SQ <setup>)} 
      {
        (SQ <'\n'> <'\techo 4827 > foo &&\n'> <'\tgit add foo &&\n'> <'\tgit commit -m "initial" &&\n'> 
          <'\tgit cat-file -p HEAD: > actual &&\n'> <'\ttest_cmp expect_initial actual &&\n'> <'\techo 11742 > foo &&\n'> 
          <'\tgit commit -a -m "update" &&\n'> <'\tgit cat-file -p HEAD: > actual &&\n'> <'\ttest_cmp expect_update actual\n'>
        )
      }
    )
    (command.SimpleCommand
      words: [{(cat)}]
      redirects: [
        (redir.Redir op:<Redir_Great '>'> fd:16777215 arg_word:{(expect)})
        (redir.HereDoc
          op: <Redir_DLess '<<'>
          fd: 16777215
          here_begin: {(EOF)}
          here_end_span_id: 68
          stdin_parts: [('index 51d27384..51d2738e 100644\n')]
        )
      ]
    )
    (C {(test_expect_success)} {(SQ <'diff does not produce ambiguous index line'>)} 
      {
        (SQ <'\n'> <'\tgit diff HEAD^..HEAD | grep index > actual &&\n'> <'\ttest_cmp expect actual\n'>)
      }
    )
    (C {(test_done)})
  ]
)