[plt-scheme] SchemeUnit confusion

In the latest SVN, I have the following program in the Definitions window.

#lang scheme/base
(require (planet schematics/schemeunit:3)
         schemeunit/text-ui)

(define BLAH
    (test-suite
    "An example suite"
    #:before (lambda () (display "Before"))
    #:after  (lambda () (display "After"))
    (test-case
      "An example test"
      (check-eq? 1 1))))

Then I try

> (run-tests BLAH)

in the Interactions window and get:

foldts: Don't know what to do with #(struct:schemeunit-test-suite ...
An example suite #<procedure:the-tests>
#<procedure:...unit.plt/3/4/base.ss:42:18>
#<procedure:...unit.plt/3/4/base.ss:43:17>).  It isn't a test case or
test suite.

What am I doing wrong?

Todd