Adding unit test.
Adding unit test.

Signed-off-by: tianhe1986 <281d452b19a59ed794600af3f9379854f1230d4f@163.com>

tianhe1986/CodeIgniter,butane/CodeIgniter,ytetsuro/CodeIgniter,butane/CodeIgniter,jim-parry/CodeIgniter,jim-parry/CodeIgniter,tianhe1986/CodeIgniter,asmdigital/CodeIgniter,tianhe1986/CodeIgniter,asmdigital/CodeIgniter,jim-parry/CodeIgniter,butane/CodeIgniter,bcit-ci/CodeIgniter,bcit-ci/CodeIgniter,bcit-ci/CodeIgniter,asmdigital/CodeIgniter,madwings/InsaneDB,tianhe1986/CodeIgniter,ytetsuro/CodeIgniter,bcit-ci/CodeIgniter,ytetsuro/CodeIgniter,madwings/InsaneDB,ytetsuro/CodeIgniter,butane/CodeIgniter,tianhe1986/CodeIgniter,madwings/InsaneDB,madwings/InsaneDB,ytetsuro/CodeIgniter,jim-parry/CodeIgniter,butane/CodeIgniter,madwings/InsaneDB,asmdigital/CodeIgniter,jim-parry/CodeIgniter,asmdigital/CodeIgniter,bcit-ci/CodeIgniter