@After
  public void tearDown() throws Exception {
    // testAppendClose closes the FileSystem, which will prevent us from closing cleanly here.
    try {
      wals.close();
    } catch (IOException exception) {
      LOG.warn("Encountered exception while closing wal factory. If you have other errors, this"
        + " may be the cause. Message: " + exception);
      LOG.debug("Exception details for failure to close wal factory.", exception);
    }
    FileStatus[] entries = fs.listStatus(new Path("/"));
    for (FileStatus dir : entries) {
      fs.delete(dir.getPath(), true);
    }
  }
WAL tests that can be reused across providers.
hbase-server/src/test/java/org/apache/hadoop/hbase/wal/TestWALFactory.java