Problems understanding test-suite

[Dirk Herrmann <dirk at ida dot ing dot tu-bs dot de>]

Hi!

In the test-suite I realize the following construct (for example in
alist.test):

(expect-failure-if (not (defined? 'sloppy-assv-ref)) 
                   (pass-if "alist: assv-ref deformed"
                            (catch 'wrong-type-arg
                                   (lambda ()
                                     (assv-ref deformed 'sloppy)
                                     #f)
                                   (lambda (key . args)
                                     #t))))

What I don't understand is:  Why is the existence of 'sloppy-assv-ref
important to the outcome of the test?  Is 'sloppy-assv-ref supposed to be
a flag that controls the behaviour of assv-ref?  I could not find any
reference to sloppy-assv-ref in libguile or ice-9.

Best regards,
Dirk Herrmann