private HeapDisk createDisk() {
      int maxCachedBlockCount = cacheSize == -1 ? Integer.MAX_VALUE : (cacheSize / blockSize);
      return new HeapDisk(blockSize, Integer.MAX_VALUE, maxCachedBlockCount);
    }
Configuration for a set of test cases.
jimfs/src/test/java/com/google/common/jimfs/RegularFileTest.java