old_contents: from pyadtn.utils import *
  from nacl.utils import random
  from nacl.secret import SecretBox
  
  
  def test_randomness():
      rand1 = generate_iv()
      rand2 = generate_iv()
      assert rand1 != rand2
  
  
  def test_iv_length():
      rand = generate_iv()
      assert len(rand) == SecretBox.NONCE_SIZE
  
  
  def test_Xcryption():
      msg = b'hello'
      key = random(SecretBox.KEY_SIZE)
      enc = encrypt(msg, key)
      dec = decrypt(enc, key)
      assert msg == dec
  
  
  def test_conversion():
      hello = b'hello'
      assert s2b(b2s(hello)) == hello
  
  
  def test_mac_generator():
      mac = random_mac_address()
      digits = '0123456789abcdef'
      assert len(mac) == 17
      for i in range(17):
          if i % 3 == 2:
              assert mac[i] == ':'
          else:
              assert mac[i] in digits
  
new_contents: from pyadtn.utils import *
  from nacl.utils import random
  from nacl.secret import SecretBox
  
  
  def test_Xcryption():
      msg = b'hello'
      key = random(SecretBox.KEY_SIZE)
      enc = encrypt(msg, key)
      dec = decrypt(enc, key)
      assert msg == dec
  
  
  def test_conversion():
      hello = b'hello'
      assert s2b(b2s(hello)) == hello
  
  
  def test_mac_generator():
      mac = random_mac_address()
      digits = '0123456789abcdef'
      assert len(mac) == 17
      for i in range(17):
          if i % 3 == 2:
              assert mac[i] == ':'
          else:
              assert mac[i] in digits
subject: remove tests to deleted function