There is something fishy here. In the file there is
ExecStart=/opt/toto.sh, but the error message mentions /opt/toto/toto.sh which is obviously a different pathname. Additionally we're dealing with toto.service and spark.service (huh?), and somehow test.sh is involved in this. Maybe your real setup is somewhat complicated and maybe instead of creating and testing an mcve, you got the code and errors from the non-minimal problem and (maybe inaptly) modified the snippets while posting, so it kinda looks minimal. Please review.