Incompatibility in behaviour of "rake test" and "ruby -Itest

Hello everybody,

I had a following problem today. My test that I used to run successfully
with "ruby -Itest" is failing when it is run with "rake
test:integration".
I can't understand why.

Could you please check below the test class definition and output that
"ruby -Itest" and "rake test:integration" give me.

Thank you in advance,
Evgeny