public static void closeAndCheckForSuspects(List<File> suspectFiles) {
    StringBuilder suspectStringCollector = new StringBuilder();
    for (File suspect : suspectFiles) {
      checkSuspectFile(suspect, suspectStringCollector);
    }

    if (suspectStringCollector.length() != 0) {
      System.err.println("Suspicious strings were written to the log during this run.\n"
          + "Fix the strings or use IgnoredException.addIgnoredException to ignore.\n"
          + suspectStringCollector);

      Assert.fail("Suspicious strings were written to the log during this run.\n"
          + "Fix the strings or use IgnoredException.addIgnoredException to ignore.\n"
          + suspectStringCollector);
    }
  }
Add an appender to Log4j which sends all INFO+ messages to a separate file which will be used
later to scan for suspect strings. The pattern of the messages conforms to the original log
format so that hydra will be able to parse them.
geode-dunit/src/main/java/org/apache/geode/test/dunit/internal/DUnitLauncher.java