@Test
  public void bptree_txn_11() {
    BPlusTree bpt1 = createBPTree();
    BPlusTree bpt2 = createBPTree();
    assertNotEquals(bpt1.getComponentId(), bpt2.getComponentId());

    Transactional thing = transactional(bpt1, bpt2);

    // Commit 1
    Txn.executeWrite(
        thing,
        () -> {
          IndexTestLib.add(bpt1, 2, 1);
          IndexTestLib.add(bpt2, 3, 4, 5);
        });
    Txn.executeRead(
        thing,
        () -> {
          IndexTestLib.testIndexContents(bpt2, 3, 4, 5);
          IndexTestLib.testIndexContents(bpt1, 1, 2);
        });

    // Abort
    thing.begin(ReadWrite.WRITE);
    IndexTestLib.add(bpt1, 9, 10);
    IndexTestLib.delete(bpt2, 3, 11);
    thing.abort();
    Txn.executeRead(
        thing,
        () -> {
          IndexTestLib.testIndexContents(bpt2, 3, 4, 5);
          IndexTestLib.testIndexContents(bpt1, 1, 2);
        });

    // Commit 2
    Txn.executeWrite(
        thing,
        () -> {
          IndexTestLib.delete(bpt1, 1, 3);
          IndexTestLib.add(bpt1, 4);
          IndexTestLib.add(bpt2, 11, 12, 13);
        });
    Txn.executeRead(
        thing,
        () -> {
          IndexTestLib.testIndexContents(bpt2, 3, 4, 5, 11, 12, 13);
          IndexTestLib.testIndexContents(bpt1, 2, 4);
        });
  }
 // Two transactions, second a delete no-op.
 // Relies on all blocks not being min0size so not rebalanced.
 @Test
 public void bptree_txn_06() {
   BPlusTree bpt = createBPTree();
   int outerRootIdx1 = bpt.getRootId();
   Transactional thing = transactional(bpt);
   Txn.executeWrite(
       thing,
       () -> {
         IndexTestLib.add(bpt, 1, 2, 3);
       });
   int outerRootIdx2 = bpt.getRootId();
   assertNotEquals("After txn(1)", outerRootIdx1, outerRootIdx2);
   Txn.executeWrite(
       thing,
       () -> {
         IndexTestLib.delete(bpt, 5, 6);
       });
   int outerRootIdx3 = bpt.getRootId();
   assertNotEquals("After txn (2)", outerRootIdx1, outerRootIdx3);
   assertEquals("After txn (3)", outerRootIdx2, outerRootIdx3);
 }