Module Async.Expect_test_config
module IO : sig ... end with type 'a t = 'a Deferred.tIO monad
val flush : unit -> unit IO.tFlush whatever need to be to get pending output out on file descriptor 0.
val run : (unit -> unit IO.t) -> unitRun an IO operation until completion
val flushed : unit -> boolSynchronous check that there is no pending output on file description 0. With async, there is no guarantee that on the rhs of a
IO.bind (flush ()) ...the output is completely flushed, that's why we need this.
val upon_unreleasable_issue : Expect_test_config.Upon_unreleasable_issue.tupon_unreleasable_issuespecifies how to deal with output that should not be released even if it is accepted (e.g. backtraces). The default is`CR.