public ConcurrentHashMap<String, DefaultExecutor> getExecutorMap() {
    return executorMap;
  }
@Test
  void testInvalidCommand() throws InterpreterException {
    if (System.getProperty("os.name").startsWith("Windows")) {
      result = shell.interpret("invalid_command\ndir", context);
    } else {
      result = shell.interpret("invalid_command\nls", context);
    }
    assertEquals(Code.SUCCESS, result.code());
    assertTrue(shell.getExecutorMap().isEmpty());
  }