sms_test: add output checks

Change-Id: I4b033dc0d3d43825901308cda05c6999946b664e
diff --git a/selftest/sms_test.ok b/selftest/sms_test.ok
new file mode 100644
index 0000000..125b5c0
--- /dev/null
+++ b/selftest/sms_test.ok
@@ -0,0 +1,6 @@
+message nr. 1
+message nr. 2
+message nr. 3
+message nr. 4, from 123, to 456
+message nr. 5, from 123, to 456
+message nr. 4, from 123, to 456