(((name . "set-displayable!")
  (signature
   case-lambda
   (((procedure? predicate?) (procedure? transformer)) *)
   (((test-runner? runner) (procedure? predicate?) (procedure? transformer)) *))
  (subsigs
   (predicate? (lambda (*) boolean?))
   (transformer (lambda ((test-runner? runner) (predicate? value)) *)))
  (desc "
Adds a new display transformer to the test runner. If no test runner is
specified, adds a new display transformer to the current test runner.

For information about how the test runner transforms values, see the
documentation for `make-displayable`.

The use of this function in conjunction with `make-displayable` makes it
possible to rewrite recursive structures. For example, to translate a
custom record type for the current test runner:

    (define-record-type <my-record-type>
       (my-record-type field1 field2)
       my-record-type?
       (field1 get-field1)
       (field2 get-field2))

    (set-displayable! my-record-type?
                      (lambda (runner value)
                        (list '<my-record-type>
                              (make-displayable runner (get-field1 value))
                              (make-displayable runner (get-field2 value)))))
"))
 ((name . "make-displayable")
  (signature lambda ((test-runner? runner) value) *)
  (desc "
Attempts to make `value` displayable using the display transformers in
`runner`.

Whenever test results are written to the screen, the list of display
transformers for that test runner are used to rewrite the test results to
be writeable using `write`. This is used to make normally unprintable
values such as `define-record-type` records printable.

Whenever `make-displayable` is called with a value,
the `predicate?` of each transformer in `runner` is checked, newest first,
and if any of the `predicate?` procedures return true, the `transformer`
procedure is called with the runner as the first argument and the value
as the second argument.
"))
 ((name . "dynamic-property-set!")
  (signature
   case-lambda
   ((property value) *)
   (((test-runner? runner) property value) *))
  (desc "
Add `(cons property value)` to the dynamic property alist of runner. The
dynamic properties of the runner are printed out at the end of a run and
are discarded after the end of a test."))
 ((name . "set-verbosity!")
  (signature
   case-lambda
   ((value) *)
   (((test-runner? runner) value *)))
  (desc "
Set verbosity of the runner.

If `value` is `fails`, then only report failures. Otherwise report failures
and successes."))
 ((name . "factory")
  (signature lambda () test-runner?)
  (desc "
An SRFI-64 factory, suitable for passing to `test-runner-factory`.")))