(CommandList
  children: [
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:test_description)
          op: Equal
          rhs: {(SQ <'performance of filter-branch'>)}
          spids: [4]
        )
      ]
      spids: [4]
    )
    (C {(.)} {(./perf-lib.sh)})
    (C {(test_perf_default_repo)})
    (C {(test_checkout_worktree)})
    (C {(test_expect_success)} {(SQ <'mark bases for tests'>)} 
      {(SQ <'\n'> <'\tgit tag -f tip &&\n'> <'\tgit tag -f base HEAD~100\n'>)}
    )
    (C {(test_perf)} {(SQ <'noop filter'>)} 
      {(SQ <'\n'> <'\tgit checkout --detach tip &&\n'> <'\tgit filter-branch -f base..HEAD\n'>)}
    )
    (C {(test_done)})
  ]
)