first refactoring fr *.bats according to shellcheck

test/mail_with_sdbox.bats

@@ -21,7 +21,7 @@ setup_file() {
                 --cap-add=SYS_PTRACE \
                 -e PERMIT_DOCKER=host \
                 -e DMS_DEBUG=0 \
-                -h mail.my-domain.com -t ${NAME}
+                -h mail.my-domain.com -t "${NAME}"
     wait_for_smtp_port_in_container mail_with_sdbox_format
 }
 
@@ -30,7 +30,7 @@ teardown_file() {
 }
 
 @test "first" {
-    skip 'only used to call setup_file from setup'
+  skip 'this test must come first to reliably identify when to run setup_file'
 }
 
 
@@ -38,10 +38,11 @@ teardown_file() {
   run docker exec mail_with_sdbox_format /bin/sh -c "nc 0.0.0.0 25 < /tmp/docker-mailserver-test/email-templates/existing-user1.txt"
   assert_success
 
+  # shellcheck disable=SC2016
   repeat_until_success_or_timeout 30 docker exec mail_with_sdbox_format /bin/sh -c '[ $(ls /var/mail/localhost.localdomain/user1/mailboxes/INBOX/dbox-Mails/u.1 | wc -l) -eq 1 ]'
 }
 
 
 @test "last" {
-    skip 'only used to call teardown_file from teardown'
+  skip 'this test is only there to reliably mark the end for the teardown_file'
 }