Running seafile-controller -t will geneate the following:
seaf-server: invalid option – L
usage: seaf-server [-c config_dir] [-d seafile_dir]
failed to run “seaf-server -t” 
Furthermore, there is no config testing logic in seaf-server and also does not accept the -t option.
“seaf-server -F “%s” -c “%s” -d “%s” -L “%s” -t -f”,
Valid args in seaf-server are here:
Also, there is the ability to select debugging mode in seaf-server via the -D option, and in seafile-controller, the -G option is how you set this, however, seafile-controller does not set this arg when executing the seaf-server command.
The log level could be using another function to set via seafile_log_init but I didn’t dig into this deep enough to understand how this works.