@Test
  public void testSplitLogFileDeletedRegionDir() throws IOException {
    LOG.info("testSplitLogFileDeletedRegionDir");
    final String REGION = "region__1";
    REGIONS.clear();
    REGIONS.add(REGION);

    generateWALs(1, 10, -1);
    useDifferentDFSClient();

    Path regiondir = new Path(TABLEDIR, REGION);
    LOG.info("Region directory is" + regiondir);
    fs.delete(regiondir, true);
    WALSplitter.split(HBASELOGDIR, WALDIR, OLDLOGDIR, fs, conf, wals);
    assertFalse(fs.exists(regiondir));
  }
Sets up a log splitter with a mock reader and writer. The mock reader generates a specified
number of edits spread across 5 regions. The mock writer optionally sleeps for each edit it is
fed. After the split is complete, verifies that the statistics show the correct number of edits
output into each region.
@param numFakeEdits   number of fake edits to push through pipeline
@param bufferSize     size of in-memory buffer
@param writerSlowness writer threads will sleep this many ms per edit
hbase-server/src/test/java/org/apache/hadoop/hbase/wal/TestWALSplit.java