func TestEncodeDecode(t *testing.T) {
  data := []byte("data that I want to encrypt")
  pass := []byte("very secret password")
  for i := 0; i < 1000; i++ {
    // Encrypt the file
    b, err := x509.EncryptPEMBlock(rand.Reader,
      "RSA PRIVATE KEY",
      data,
      pass,
      x509.PEMCipherAES256)
    if err != nil {
      t.Fatalf("err: %s", err)
    }
    bf := &bytes.Buffer{}

    err = pem.Encode(bf, b)
    if err != nil {
      t.Fatalf("err: %s", err)
    }
    privateKey := bf.Bytes()

    PEMBlock, _ := pem.Decode(privateKey)
    if PEMBlock == nil {
      t.Fatal("")
    }

    if x509.IsEncryptedPEMBlock(PEMBlock) {
      decryptedPrivateKeyBytes, err := x509.DecryptPEMBlock(PEMBlock, []byte("wrooooong"))
      if err == nil {
        if string(decryptedPrivateKeyBytes) != string(data) {
          t.Fatalf("this is not supposed to happen: %s", decryptedPrivateKeyBytes)
        }
      }
    }
  }
}