Testing perl

Perl ships with an extensive test suite, covering the interpreter itself and most of the modules. To run a full test, use

	(cd t && ./perl harness)

or just

	make test

This works just as well with perl-cross — assuming you do it on the target from within a full perl build tree. Depending on the target, the latter part may not be practical, and actually makes little sense when you think of it.

perl-cross provides an alternative way for on-target testing: testpack, tarball with the tests (and little else) that can be transferred to the target. It's must smaller than the perl tree, ~23MB instead of 150+MB, and unlike make test it's set up to test the perl that's already installed in its proper location.

To make the pack, run

	make testpack

then transfer TESTPACK.tar.gz to the target, unpack it there and do

	(cd TESTPACK/t/ && ./perl harness)

Run

	make clean-testpack

in the source tree to remove TESTPACK/ if necessary after TESTPACK.tar.gz has been built.

At this point testpack does not include all the tests that make test does. So if you need to make absolutely sure the perl passes every test, do transfer the whole build tree and run make test instead. However, testpack should be more than enough to catch bad cross-compiling issues.

Caveats

Just like the rest of the language, perl testsuite is one big hack with a lot of counter-intuitive and counter-productive issues no-one bothers to fix. Following the tradition, I merely document some of them here.

Some of the tests scan perl source tree and/or check it against MANIFEST. If you did some equivalent of "make DESTDIR=`pwd`/out install" within the source tree, make sure to remove out/ before running tests.
It may be tempting to run "perl harness" instead of "./perl harness". It will work, however the actual tests will still be run using ./perl, so if you do that make sure "perl" and "./perl" are the same.
The tests (NOT the harness!) decide whether to run themselves by checking $Config{extensions}.
Most tests do reset @INC and populate it with values like "../lib" etc. Testpack mitigates it somewhat, but it's still there.
(harness only) $PERL5LIB value is ignored, however $PERL5LIB_TEST will be used. See t/TEST for reference.
Test for some cpan/ modules do different things depending on $PERL_CORE value. Even in testpack, $PERL_CORE will be 1. Don't ask. Google for "dual-life perl module".
To run a single test, use something like
```
		./perl harness ../cpan/Archive-Extract/t/01_Archive-Extract.t
	
```
from the t/ directory. It is possible to run some of the tests without harness, but others will fail with bogus error messages.

Tests excluded from testpack

Check TESTPACK.px, namely %exclude hash at the top.

Short summary: porting/, most of ExtUtils, CPAN meta-modules and some XS stuff is excluded, the rest should work. Given the nature of the excluded tests, they will probably never work well with cross-builds. Also, XS::APItest and anything that depends on it.