I created the service, checked how it works: starts, stops, adds to the startup, and the like. Then just deleted the file from /etc/systemd/system/ with his service file. Performed systemctl daemon-reload and forget about it all. The server is already rebooted several times.
Now it was necessary to check the services that are performed systemctl list-units -t service and saw this test the service that you thought was removed:
● test.service not-found failed failed test.service
How to remove it completely?