testing.Short() returns unexpected value on testing.TestMain(*testing.M). (https://github.com/golang/go/issues/9825)

README.md

This repo showing testing.Short() returns unexpected value on testing.TestMain(*testing.M).
please do go test -short.

Here is result in my environment

$ go version
go version go1.4 linux/amd64
$ go test -short
false   on TestMain
true    on TestSomething
PASS
ok      _/home/umisama/testing  0.008s

doc.go

// This repo showing testing.Short() returns unexpected value on testing.TestMain(*testing.M).
package main

main_test.go

package main

import (
	"os"
	"testing"
)

func TestMain(m *testing.M) {
	println(testing.Short(), "\ton TestMain")
	os.Exit(m.Run())
}

func TestSomething(t *testing.T) {
	println(testing.Short(), "\ton TestSomething")
}