test-suite

[Dirk Herrmann]

Hello everybody.

Based on Thi's initiative to provide some more tests for guile's
test-suite (thanks!, especially for finding a set of bugs :-), I have
changed the module (test-suite lib) to provide some additional macros that
are meant to make writing tests easier:

;;;; Convenience macros to test for exceptions
;;;;
;;;; The following macros take exception parameters which are pairs
;;;; (type . message), where type is a symbol that denotes an exception type
;;;; like 'wrong-type-arg or 'out-of-range, and message is a string holding a
;;;; regular expression that describes the error message for the exception
;;;; like "Argument .* out of range".
;;;;
;;;; * (pass-if-exception name exception body) will pass if the execution of
;;;;   body causes the given exception to be thrown.  If no exception is
;;;;   thrown, the test fails.  If some other exception is thrown, is is an
;;;;   error.
;;;; * (expect-fail-exception name exception body) will pass unexpectedly if
;;;;   the execution of body causes the given exception to be thrown.  If no
;;;;   exception is thrown, the test fails expectedly.  If some other
;;;;   exception is thrown, it is an error.

The macros pass-if-exception and expect-fail-exception are basically a
generalization of the concept provided by Thi.  Some minor differences:
An exception is characterized as a pair (type . message) instead of just a
message string.  Further, with the additional form expect-fail-exception
it is possible to express that it is expected that the error reporting
will fail.  Therefore, the test-suite does not currently report any
unexpected failures, but the number of expected failures has increased.
(not sure whether to put a smiley of a frowney behind that sentence.)

What still misses is a convenient way to express that for some code guile
should throw a certain exception, but guile does throw some other
exception which does not actually fit to the situation.  This is also a
kind of expected failure, because the error reporting mechanism should be
fixed in such a case.  If there is not objection, I will provide an
additional macro expect-fail-false-exception:

;;;; * (expect-fail-false-exception name exception f-exception body) will pass
;;;;   unexpectedly if the execution of body causes exception to be thrown.
;;;;   It will fail expectedly if f-exception is thrown.  If no exception is
;;;;   thrown, the test is unresolved.  If some other exception is thrown, it
;;;;   is an error.

Best regards, 
Dirk Herrmann