test/test-execute/exec-environment-no-substitute.service

[Unit]
Description=Test for No Environment Variable Substitution

[Service]
ExecStart=/bin/sh -x -c 'test "$${VAR1-unset}" = "unset" && test "$${VAR2}" = "word3" && test "$${VAR3-unset}" = \'$word 5 6\''
ExecStart=:/bin/sh -x -c 'test "$${VAR1-unset}" != "unset" && test "$${VAR2}" != "word3" && test "$${VAR3-unset}" != \'$word 5 6\''
Type=oneshot
Environment="VAR2=word3" "VAR3=$word 5 6"