@Test
public void testDefaultConstructor() {

  Drbg drbg = new AesCtrDrbg();
  Drbg otherDrbg = new AesCtrDrbg();
  byte[] bytes = new byte[16];
  drbg.nextBytes(bytes);
  byte[] otherBytes = new byte[16];
  otherDrbg.nextBytes(bytes);
  // sanity check that different drbg produce different results
  Assert.assertThat(bytes, IsNot.not(IsEqual.equalTo(otherBytes)));
}