class Minitest::Reporters::HtmlReporter

def location(exception)
  last_before_assertion = ''
  exception.backtrace.reverse_each do |s|
    break if s =~ /in .(assert|refute|flunk|pass|fail|raise|must|wont)/
    last_before_assertion = s
  end
  last_before_assertion.sub(/:in .*$/, '')
end