code: @Test public void testUserSpecifiedLayers() throws Exception {
    byte[] alphabet="ABCDEFGHIJKLMNOPQRSTUVWXYZ".getBytes(LATIN_1);
    AztecCode aztec=Encoder.encode(alphabet,25,-2);
    assertEquals(2,aztec.getLayers());
    assertTrue(aztec.isCompact());
    aztec=Encoder.encode(alphabet,25,32);
    assertEquals(32,aztec.getLayers());
    assertFalse(aztec.isCompact());
    try {
      Encoder.encode(alphabet,25,33);
      fail("Encode should have failed.  No such thing as 33 layers");
    }
   catch (  IllegalArgumentException expected) {
    }
    try {
      Encoder.encode(alphabet,25,-1);
      fail("Encode should have failed.  Text can't fit in 1-layer compact");
    }
   catch (  IllegalArgumentException expected) {
    }
  }
  