systemd/test/test-execute/exec-environmentfile.service

[Unit]
Description=Test for EnvironmentFile

[Service]
ExecStart=/bin/sh -c 'exit $(test "$VAR1" = "word1 word2") && $(test "$VAR2" = word3) && $(test "$VAR3" = \'$word 5 6\')'
Type=oneshot
EnvironmentFile=/tmp/test-exec_environmentfile.conf