smbj单元测试用例

该测试用例基于OpenHarmony系统下，导出的接口进行单元测试

单元测试用例覆盖情况

接口名	是否通过	备注
exists(path, callback)	pass
mkdir(path, callback)	pass
readdir(path, callback)	pass
readFile(filename: string, options?: { encoding: 'UTF-8' }, callback?: any)	pass
rename(oldPath, newPath, callback)	pass
writeFile(filename, data, encoding?: string, callback?: any)	pass
rmdir(path, callback)	pass
unlink(path, callback)	pass
close()	pass