is( $thing->foo(), 42, "foo is 42" ) or diag $thing->as_string();

##</code><code>##

HARNESS_PERL_SWITCHES="-d"

##</code><code>##

$ make testdb TEST_FILE=t/mytest.t          # ExtUtils::MakeMaker

$ Build testdb --test_files t\02_trivial.t  # Module::Build