@Test
  public void testSplit() throws IOException {
    generateWALs(-1);
    splitAndCount(NUM_WRITERS, NUM_WRITERS * ENTRIES);
  }
@return set of wal names present prior to split attempt.
@throws IOException if the split process fails
hbase-server/src/test/java/org/apache/hadoop/hbase/wal/TestWALSplit.java