text: #include "stdio.h"
  #include "stdlib.h"
  #include "unistd.h"
  
  void test_mkdir(void){
      TEST_START(__func__);
      int rt, fd;
  
      rt = mkdir("test_mkdir", 0666);
      printf("mkdir ret: %d\n", rt);
      assert(rt != -1);
      fd = open("test_mkdir", O_RDONLY | O_DIRECTORY);
      if(fd > 0){
          printf("  mkdir success.\n");
          close(fd);
      }
      else printf("  mkdir error.\n");
      TEST_END(__func__);
  }
  
  int main(void){
      test_mkdir();
      return 0;
  }
  