os.close();
assertTrue(bucket.isRAMBucket());
assertEquals(len, bucket.size());
bucket.getInputStream().close();
TempRandomAccessBuffer raf = (TempRandomAccessBuffer) bucket.toRandomAccessBuffer();
raf.migrateToDisk();
assertTrue(raf.hasMigrated());
File f = ((PooledFileRandomAccessBuffer) raf.getUnderlying()).file;
assertTrue(f.exists());
raf.free();
assertFalse(f.exists());