+# data having line with (logical, doubled on wire) single dot
+server PORT_S
+220 ESMTP
+EHLO
+250 OK
+MAIL FROM:
+250 Sender OK
+RCPT TO:
+250 Recipient OK
+DATA
+354 Send data
+.
+250 OK
+QUIT
+250 OK
+****
+exim -bs -odf
+EHLO myhost.test.ex
+MAIL FROM:<CALLER@myhost.test.ex>
+RCPT TO:<userx@domain.com>
+DATA
+Subject: singledot test
+
+This data has a line with a single dot... next:
+..
+and this is the line right after.
+Next we have a line with a leading dot:
+..test
+and this is the next line.
+
+.
+QUIT
+****