@Test
  public void simpleWriteRead() {

    byte primaryRingSizeInBits = 9;
    byte byteRingSizeInBits = 18;

    Pipe ring = new Pipe(new PipeConfig(primaryRingSizeInBits, byteRingSizeInBits, null, FROM));
    ring.initBuffers();

    int messageSize = FROM.fragDataSize[FRAG_LOC];

    int varDataMax = (ring.byteMask / (ring.mask >> 1)) / messageSize;
    int testSize = ((1 << primaryRingSizeInBits) / messageSize) - 1; // room for EOF

    writeTestValue(ring, varDataMax, testSize);

    // now read the data back
    int FIELD_LOC =
        FieldReferenceOffsetManager.lookupFieldLocator(SINGLE_MESSAGE_NAMES[0], FRAG_LOC, FROM);

    int k = testSize;
    while (PipeReader.tryReadFragment(ring)) {

      --k;
      assertTrue(PipeReader.isNewMessage(ring));
      int messageIdx = PipeReader.getMsgIdx(ring);
      if (messageIdx < 0) {
        return;
      }
      testReadValue(ring, varDataMax, testSize, FIELD_LOC, k, messageIdx);
    }
  }
  @Test
  public void simpleWriteReadThreaded() {

    final byte primaryRingSizeInBits = 7; // this ring is 2^7 eg 128
    final byte byteRingSizeInBits = 16;
    final Pipe ring =
        new Pipe(new PipeConfig(primaryRingSizeInBits, byteRingSizeInBits, null, FROM));
    ring.initBuffers();

    final int messageSize = FROM.fragDataSize[FRAG_LOC];

    final int varDataMax = (ring.byteMask / (ring.mask >> 1)) / messageSize;
    final int testSize = (1 << primaryRingSizeInBits) / messageSize;

    Thread t =
        new Thread(
            new Runnable() {

              @Override
              public void run() {
                writeTestValue(ring, varDataMax, testSize);
              }
            });
    t.start();

    // now read the data back

    int FIELD_LOC =
        FieldReferenceOffsetManager.lookupFieldLocator(SINGLE_MESSAGE_NAMES[0], FRAG_LOC, FROM);

    int k = testSize;
    while (k > 0) {

      // This is the example code that one would normally use.

      // System.err.println("content "+ring.contentRemaining(ring));
      if (PipeReader.tryReadFragment(
          ring)) { // this method releases old messages as needed and moves pointer up to the next
        // fragment
        k--; // count down all the expected messages so we stop this test at the right time

        assertTrue(PipeReader.isNewMessage(ring));
        int messageIdx = PipeReader.getMsgIdx(ring);
        if (messageIdx < 0) {
          return;
        }
        testReadValue(ring, varDataMax, testSize, FIELD_LOC, k, messageIdx);

      } else {
        // unable to read so at this point
        // we can do other work and try again soon
        Thread.yield();
      }
    }
  }