private void runSmallBlockersDiscard(BuddyAllocator a,
      int baseSize, boolean deallocOneFirst, boolean deallocOneSecond) {
    LlapAllocatorBuffer[] initial = prepareAllocatorWithSmallFragments(
        a, baseSize, deallocOneFirst, deallocOneSecond, true);
    int bigAllocSize = baseSize * 4;
    LlapAllocatorBuffer[] after = allocate(a, 1, bigAllocSize, 1 + initial.length);
    LOG.info("After: " + a.testDump());
    checkInitialValues(initial, 2, 4);
    checkTestValue(after[0], 1 + initial.length, null, true);
  }
This relies on allocations basically being sequential, no internal reordering. Rather,
the specific paths it takes do; all the scenarios should work regardless of allocation.
llap-server/src/test/org/apache/hadoop/hive/llap/cache/TestBuddyAllocatorForceEvict.java