private static WAL createWALCompatibleWithFaultyFileSystem(String callingMethod,
    Configuration conf, TableName tableName) throws IOException {
    final Path logDir = TEST_UTIL.getDataTestDirOnTestFS(callingMethod + ".log");
    final Configuration walConf = new Configuration(conf);
    CommonFSUtils.setRootDir(walConf, logDir);
    return new WALFactory(walConf, callingMethod)
      .getWAL(RegionInfoBuilder.newBuilder(tableName).build());
  }
Create a WAL outside of the usual helper in
{@link HBaseTestingUtil#createWal(Configuration, Path, RegionInfo)} because that method doesn't
play nicely with FaultyFileSystem. Call this method before overriding {@code fs.file.impl}.
@param callingMethod a unique component for the path, probably the name of the test method.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestHRegion.java