@private
Minitest 5.x requires this accessor to be available. See github.com/seattlerb/minitest/blob/38f0a5fcbd9c37c3f80a3eaad4ba84d3fc9947a0/lib/minitest/assertions.rb#L8
It is not required for other extension libraries, and RSpec does not report or make this information available to formatters.
# File lib/rspec/core/minitest_assertions_adapter.rb, line 23 def assertions @assertions ||= 0 end