linux shell cp hidden files or folders

cp -a / home / test / / root / tmp / The
above command is to copy all files in the / home / test / directory and below to / root / tem /, the effect should be: / root / tmp / test / **** With the -a parameter, you can also copy the hidden files . I tried this.
In addition, if the genus is cp -a / home / test / * / root / tmp / Copy all the files in the / home / test directory without including the directory itself. The effect is: / root / tmp / ***** In this case, it is indeed impossible to copy the hidden files , but you can replace * with . Write this way: cp -a / home / test /. / Root / tmp so that all files can be copied over