test-sysdef-asdf failing

[Robert Goldman]

This block of test is failing:

(DBG "Load ASDF with proper configuration: should find asdf.asd from the
source above")
(initialize-source-registry
 `(:source-registry
   (:directory ,*asdf-directory*)
   (:directory ,*uiop-directory*)
   :ignore-inherited-configuration))
(clear-system "asdf")
(load-system :asdf)
;; This time we found it, but it was skipped because the version was the
same
(assert-equal nil (system-source-file (find-system :asdf)))

Can you explain why it's correct to have the SYSTEM-SOURCE-FILE of ASDF
be NIL?

I'm sorry, but I simply don't understand what you are testing here, or
why the right answer is NIL.  I think there's some critical fact about
the system that you expect to hold after the immediately previous call
to UPGRADE ASDF, but I don't know what it is.

This is what's in the log file:

While evaluating the form starting at line 48, column 0
  of #P"/Users/rpg/lisp/asdf/test/test-sysdef-asdf.script":
TEST ABORTED: These two expressions fail comparison with EQUAL:
 NIL evaluates to NIL
 (SYSTEM-SOURCE-FILE (FIND-SYSTEM :ASDF)) evaluates to
#P"/Users/rpg/lisp/asdf/asdf.asd"

Thanks,
r