Perl bindings tests don't seem to work

The test subversion/bindings/swig/perl/native/t/9wc.t was added
recently, it's failing on the openbsd buildbot but passes on my Linux
box. The test contains:

# Check the first member of the returned array.
# TEST
isa_ok($externals->[0], '_p_svn_wc_external_item2_t');
# TEST
ok($externals->[0]->target_dir(), 'project1');
# TEST
ok($externals->[0]->url(), 'http://svn.example.com/repos/project1');
# TEST
ok($externals->[0]->revision(), 'svn_opt_revision_t');
# TEST
ok($externals->[0]->revision()->kind(), $SVN::Core::svn_opt_revision_head);
# TEST
ok($externals->[0]->peg_revision(), 'svn_opt_revision_t');
# TEST
ok($externals->[0]->peg_revision()->kind(),
   $SVN::Core::svn_opt_revision_head);

# Check the second member
# TEST
isa_ok($externals->[0], '_p_svn_wc_external_item2_t');
# TEST
ok($externals->[0]->target_dir(), 'Project 2');
# TEST
ok($externals->[0]->url(), '^/repos/project2');
# TEST
ok($externals->[0]->revision(), 'svn_opt_revision_t');
# TEST
ok($externals->[0]->revision()->kind(), $SVN::Core::svn_opt_revision_head);
# TEST
ok($externals->[0]->peg_revision(), 'svn_opt_revision_t');
# TEST
ok($externals->[0]->peg_revision()->kind(),
   $SVN::Core::svn_opt_revision_head);

Note that it checks externals[0] twice rather than checking externals[0]
and externals[1]. If I change the test to check externals[2]

isa_ok($externals->[2], '_p_svn_wc_external_item2_t');

I get failures because only externals[0] and externals[1] exist.
However if I change the other bits

ok($externals->[0]->url(), 'foobar');

the test still passes.

What's going on? How are these tests supposed to work?

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