(command.CommandList
  children: [
    (command.ShAssignment
      pairs: [
        (assign_pair
          lhs: (sh_lhs_expr.Name name:test_description)
          op: assign_op.Equal
          rhs: {(SQ <'various @{whatever} syntax tests'>)}
          spids: [4]
        )
      ]
    )
    (C {<.>} {<'./test-lib.sh'>})
    (C {<test_expect_success>} {(SQ <setup>)} 
      {(SQ <'\n'> <'\ttest_commit one &&\n'> <'\ttest_commit two\n'>)}
    )
    (command.ShFunction
      name: check_at
      body: 
        (BraceGroup
          children: [
            (command.AndOr
              ops: [Id.Op_DAmp Id.Op_DAmp]
              children: [
                (command.Simple
                  words: [{<echo>} {(DQ ($ Id.VSub_Number '$2'))}]
                  redirects: [(redir op:<Id.Redir_Great '>'> loc:(redir_loc.Fd fd:1) arg:{<expect>})]
                  do_fork: T
                )
                (command.Simple
                  words: [
                    {<git>}
                    {<log>}
                    {<-1>}
                    {<--format> <Id.Lit_Equals '='> <Id.Lit_Other '%'> <s>}
                    {(DQ ($ Id.VSub_Number '$1'))}
                  ]
                  redirects: [(redir op:<Id.Redir_Great '>'> loc:(redir_loc.Fd fd:1) arg:{<actual>})]
                  do_fork: T
                )
                (C {<test_cmp>} {<expect>} {<actual>})
              ]
            )
          ]
        )
    )
    (C {<test_expect_success>} {(SQ <'@{0} shows current'>)} {(SQ <'\n'> <'\tcheck_at @{0} two\n'>)})
    (C {<test_expect_success>} {(SQ <'@{1} shows old'>)} {(SQ <'\n'> <'\tcheck_at @{1} one\n'>)})
    (C {<test_expect_success>} {(SQ <'@{now} shows current'>)} {(SQ <'\n'> <'\tcheck_at @{now} two\n'>)})
    (C {<test_expect_success>} {(SQ <'@{2001-09-17} (before the first commit) shows old'>)} 
      {(SQ <'\n'> <'\tcheck_at @{2001-09-17} one\n'>)}
    )
    (C {<test_expect_success>} {(SQ <'silly approxidates work'>)} 
      {(SQ <'\n'> <'\tcheck_at @{3.hot.dogs.on.2001-09-17} one\n'>)}
    )
    (C {<test_expect_success>} {(SQ <'notice misspelled upstream'>)} 
      {(SQ <'\n'> <'\ttest_must_fail git log -1 --format=%s @{usptream}\n'>)}
    )
    (C {<test_expect_success>} {(SQ <'complain about total nonsense'>)} 
      {(SQ <'\n'> <'\ttest_must_fail git log -1 --format=%s @{utter.bogosity}\n'>)}
    )
    (C {<test_done>})
  ]
)