### Question:
ContainerLaunch implements Callable<Integer> { @VisibleForTesting public static String expandEnvironment(String var, Path containerLogDir) { var = var.replace(ApplicationConstants.LOG_DIR_EXPANSION_VAR, containerLogDir.toString()); var = var.replace(ApplicationConstants.CLASS_PATH_SEPARATOR, File.pathSeparator); if (Shell.WINDOWS) { var = var.replaceAll("(\\{\\{)|(\\}\\})", "%"); } else { var = var.replace(ApplicationConstants.PARAMETER_EXPANSION_LEFT, "$"); var = var.replace(ApplicationConstants.PARAMETER_EXPANSION_RIGHT, ""); } return var; } ContainerLaunch(Context context, Configuration configuration,
      Dispatcher dispatcher, ContainerExecutor exec, Application app,
      Container container, LocalDirsHandlerService dirsHandler,
      ContainerManagerImpl containerManager); @VisibleForTesting static String expandEnvironment(String var,
      Path containerLogDir); @Override @SuppressWarnings("unchecked") // dispatcher not typed Integer call(); @SuppressWarnings("unchecked") // dispatcher not typed void cleanupContainer(); static String getRelativeContainerLogDir(String appIdStr,
      String containerIdStr); void sanitizeEnv(Map<String, String> environment, Path pwd,
      List<Path> appDirs, List<String> userLocalDirs, List<String>
      containerLogDirs,
      Map<Path, List<String>> resources,
      Path nmPrivateClasspathJarDir); static String getExitCodeFile(String pidFile); static final String CONTAINER_SCRIPT; static final String FINAL_CONTAINER_TOKENS_FILE; }### Answer:
@Test(timeout = 10000) public void testEnvExpansion() throws IOException { Path logPath = new Path("/nm/container/logs"); String input = Apps.crossPlatformify("HADOOP_HOME") + "/share/hadoop/common/*" + ApplicationConstants.CLASS_PATH_SEPARATOR + Apps.crossPlatformify("HADOOP_HOME") + "/share/hadoop/common/lib/*" + ApplicationConstants.CLASS_PATH_SEPARATOR + Apps.crossPlatformify("HADOOP_LOG_HOME") + ApplicationConstants.LOG_DIR_EXPANSION_VAR; String res = ContainerLaunch.expandEnvironment(input, logPath); if (Shell.WINDOWS) { Assert.assertEquals("%HADOOP_HOME%/share/hadoop/common/*;" + "%HADOOP_HOME%/share/hadoop/common/lib/*;" + "%HADOOP_LOG_HOME%/nm/container/logs", res); } else { Assert.assertEquals("$HADOOP_HOME/share/hadoop/common/*:" + "$HADOOP_HOME/share/hadoop/common/lib/*:" + "$HADOOP_LOG_HOME/nm/container/logs", res); } System.out.println(res); }