func HasExternalNetwork() bool {
	return !testing.Short()
}
HasExternalNetwork reports whether the current system can use
external (non-localhost) networks.
package testenv
import (
	"os"
	"runtime"
	"strings"
	"testing"
)
func Builder() string {
	return os.Getenv("GO_BUILDER_NAME")
}
func HasGoBuild() bool {
	switch runtime.GOOS {
	case "android", "nacl":
		return false
	case "darwin":
		if strings.HasPrefix(runtime.GOARCH, "arm") {
			return false
		}
	}
	return true
}
func MustHaveGoBuild(t *testing.T) {
	if !HasGoBuild() {
		t.Skipf("skipping test: 'go build' not available on %s/%s", runtime.GOOS, runtime.GOARCH)
	}
}
func HasGoRun() bool {
	return HasGoBuild()
}
func MustHaveGoRun(t *testing.T) {
	if !HasGoRun() {
		t.Skipf("skipping test: 'go run' not available on %s/%s", runtime.GOOS, runtime.GOARCH)
	}
}
func HasExec() bool {
	switch runtime.GOOS {
	case "nacl":
		return false
	case "darwin":
		if strings.HasPrefix(runtime.GOARCH, "arm") {
			return false
		}
	}
	return true
}
func MustHaveExec(t *testing.T) {
	if !HasExec() {
		t.Skipf("skipping test: cannot exec subprocess on %s/%s", runtime.GOOS, runtime.GOARCH)
	}
}