Using minitest methods in capybara ruby implementation?

Im very new at ruby coding and I always use capybara native methods. Now, I need to use some assert methods for unit testing only available in rspec matchers or minitest. Rspec was discarded because some gem trouble in system machine...so.....minitest is the choice.

My question is:

Can only access to minitest methods using class like this? (see in documentation)

require "minitest/autorun"

class myTest < Minitest::Test

If I already have my class like this:

class myTest < BasePageExample

def method1()
  "needed assert_equal(.............)"
end
end

How can I import minitest for my existant class and use assert_equal method???

Thanks!!!