Go guard file. Slightly more advanced version.

Guardfile

require 'guard'
require 'guard/plugin'

class Guard::Mygo < Guard::Plugin
  def run_all
    system 'go test ./...'
  end

  def run_on_changes(paths)
    paths.each do |file|
      file.sub!(/\.go\Z/, '_test.go') unless file.scan(/_test\.go/).length > 0
      unless File.exist?(file)
        puts "#{file} does not exist"
        next
      end

      puts "Running #{file};"
      system "go test #{file}"
      puts
    end
  end
end

guard :mygo do
  watch(%r{.*?.go})
end