After doing modifications to your fstab file, you might want to test its validity so you don't get errors when you reboot your computer. Bellow is a command with different configurations depending of your needs.
The simplest way is to use the mount command. The -a flag says to mount all the filesystems present in the fstab file.
Note that this command will only mount all the not-yet-mounted filesystems.
In the case you want to do a dry-run, you can run the following command.
The flag -f stands for fake and the verbose flag -v will display errors if any.