Fixed. MRI 2.5 should be disabled now.

This happens when you have MRI 2.50 selected. Tests work when you change them to MRI 3.

I will try to disable 2.5.

For Ruby version, the tests are not valid
Even if I change it manually in test sample, attempt will fail so it is not possible to validate the kata

--> the method is not at the right position in the code, called before being defined
#<NoMethodError: undefined method `do_test' for main:Object>

--> the method 'expect' is valid for Rspec but not with the framework of Codewars
--> should use Test.assert_equals instead