private static void assertFileExists(String fileName) throws IOException {
    boolean found = Files.walk(Paths.get(System.getProperty("java.io.tmpdir"))).anyMatch(p -> p.endsWith(fileName));
    assertTrue(found, "File " + fileName + " was not found under " + System.getProperty("java.io.tmpdir"));
  }
Tests for the log4j configuration of the LLAP daemons.
llap-server/src/test/org/apache/hadoop/hive/llap/daemon/impl/TestLlapDaemonLogging.java