Undeclared dependencies

[eserte]

The test suite fails if JSON.pm is not installed:

PERL_DL_NONLAZY=1 "/usr/local/bin/perl" "-MExtUtils::Command::MM" "-MTest::Harness" "-e" "undef *Test::Harness::Switches; test_harness(0, 'blib/lib', 'blib/arch')" t/*.t
Can't locate JSON.pm in @INC (you may need to install the JSON module) (@INC contains: ... .) at t/System.t line 5.
BEGIN failed--compilation aborted at t/System.t line 5.
t/System.t .. 
Dubious, test returned 2 (wstat 512, 0x200)
No subtests run 

Also undeclared: Test::Output.