diff

# File lib/minitest/unit.rb, line 89
    def self.diff
      @diff = if (RbConfig::CONFIG['host_os'] =~ /mswin|mingw/ &&
                  system("diff.exe", __FILE__, __FILE__)) then
                "diff.exe -u"
              elsif Minitest::Unit::Guard.maglev? then # HACK
                "diff -u"
              elsif system("gdiff", __FILE__, __FILE__)
                "gdiff -u" # solaris and kin suck
              elsif system("diff", __FILE__, __FILE__)
                "diff -u"
              else
                nil
              end unless defined? @diff

      @diff
    end