Classify a deliver_sm by esm_class and document the messageDlr precondition

test/dlr.test.ts

@@ -1,17 +1,22 @@
 import assert from 'node:assert/strict';
 import test, { describe } from 'node:test';
+import { consts } from '../src/defs/constants.ts';
 import { dlrFromPdu, parseReceipt, receiptCodes } from '../src/dlr.ts';
 import { objToPdu, pduToObj } from '../src/pdu.ts';
 import type { PduObject, TlvInput } from '../src/pdu.ts';
 
 const receiptText = 'id:0195f0c7 sub:001 dlvrd:001 submit date:2508251430 done date:2508251431 stat:DELIVRD err:000 text:hello';
 
-function deliverSm(message: string, tlvs?: Record<string, TlvInput>): PduObject {
+function deliverSm(
+	message: string,
+	tlvs?: Record<string, TlvInput>,
+	esmClass: number = consts.ESM_CLASS.MC_DELIVERY_RECEIPT,
+): PduObject {
 	const { buffer } = objToPdu({
 		cmdName: 'deliver_sm',
 		params: {
 			destination_addr: '46701113311',
-			esm_class: 4,
+			esm_class: esmClass,
 			short_message: message,
 			source_addr: '46709771337',
 		},
@@ -112,8 +117,40 @@ describe('dlrFromPdu()', () => {
 		assert.equal(dlrFromPdu(deliverSm('id:x stat:DELIVRD done date:2501012560'))?.doneDate, undefined);
 	});
 
-	test('returns nothing when the PDU identifies no message', () => {
-		assert.equal(dlrFromPdu(deliverSm('just a normal sms')), undefined);
+	test('returns nothing when an unmarked deliver_sm identifies no message', () => {
+		assert.equal(dlrFromPdu(deliverSm('just a normal sms', undefined, 0)), undefined);
+	});
+
+	test('still reads the body when the peer marks no message type', () => {
+		const dlr = dlrFromPdu(deliverSm(receiptText, undefined, 0));
+
+		assert.ok(dlr);
+		assert.equal(dlr.smsId, '0195f0c7');
+		assert.equal(dlr.statusMsg, 'DELIVERED');
+	});
+
+	test('reports a marked receipt whose body it cannot read, rather than an inbound message', () => {
+		const dlr = dlrFromPdu(deliverSm('a receipt in a format nobody documented'));
+
+		assert.ok(dlr);
+		assert.equal(dlr.smsId, undefined);
+		assert.equal(dlr.statusMsg, 'UNKNOWN');
+		assert.equal(dlr.statusId, 7);
+
+		const withUdh = consts.ESM_CLASS.MC_DELIVERY_RECEIPT | consts.ESM_CLASS.UDH_INDICATOR;
+
+		assert.ok(dlrFromPdu(deliverSm(receiptText, undefined, withUdh)));
+	});
+
+	test('leaves a message the peer marked as another type to arrive as an SMS', () => {
+		for (const esmClass of [
+			consts.ESM_CLASS.CONVERSATION_ABORT,
+			consts.ESM_CLASS.DELIVERY_ACKNOWLEDGEMENT,
+			consts.ESM_CLASS.INTERMEDIATE_DELIVERY,
+			consts.ESM_CLASS.USER_ACKNOWLEDGEMENT,
+		]) {
+			assert.equal(dlrFromPdu(deliverSm(receiptText, undefined, esmClass)), undefined);
+		}
 	});
 
 	test('exposes the raw receipt alongside the resolved fields', () => {

test/session-extras.test.ts

@@ -57,7 +57,7 @@ describe('merged delivery reports', () => {
 		const merged = once<MessageDlr>(resolve => { session.on('messageDlr', resolve); });
 		const perSegment: string[] = [];
 
-		session.on('dlr', dlr => perSegment.push(dlr.smsId));
+		session.on('dlr', dlr => perSegment.push(dlr.smsId ?? ''));
 
 		const [sms] = await Promise.all([
 			incoming.then(async received => {

test/session.test.ts

@@ -711,6 +711,34 @@ describe('receiving', () => {
 		assert.equal(answered.pduObj.params.message_id, 'inbound-id');
 	});
 
+	test('hands a client a receipt it cannot read as a dlr rather than as an sms', async t => {
+		const { peer, session } = await inbound(t);
+		const reported = once<Dlr>(resolve => { session.on('dlr', resolve); });
+		let messages = 0;
+
+		session.on('sms', () => { messages++; });
+
+		const delivered = peer.send({
+			cmdName: 'deliver_sm',
+			params: {
+				destination_addr: '46709771337',
+				esm_class: consts.ESM_CLASS.MC_DELIVERY_RECEIPT,
+				short_message: 'a receipt in a format nobody documented',
+				source_addr: '46701113311',
+			},
+		});
+		const dlr = await raceWithin(2000, reported);
+
+		assert.ok(dlr, 'esm_class marks it a receipt, so nothing else may claim it');
+		assert.equal(dlr.smsId, undefined);
+		assert.equal(messages, 0);
+
+		const answered = await delivered;
+
+		assert.ok(answered.pduObj);
+		assert.equal(answered.pduObj.cmdName, 'deliver_sm_resp');
+	});
+
 	test('reassembles a multipart inbound SMS before the sms event', async t => {
 		const message = 'Inbound lorem ipsum dolor sit amet consectetur, '.repeat(6);
 		const { peer, session } = await inbound(t);
@@ -757,7 +785,7 @@ describe('delivery reports', () => {
 
 		assert.ok(session);
 
-		const dlr = once<[{ smsId: string; statusMsg: string }, PduObject]>(resolve => {
+		const dlr = once<[Dlr, PduObject]>(resolve => {
 			session.on('dlr', (report, pduObj) => { resolve([report, pduObj]); });
 		});
 
@@ -873,7 +901,7 @@ describe('delivery reports', () => {
 		const perSegment: string[] = [];
 		let merged = 0;
 
-		session.on('dlr', dlr => perSegment.push(dlr.smsId));
+		session.on('dlr', dlr => perSegment.push(dlr.smsId ?? ''));
 		session.on('messageDlr', () => { merged++; });
 
 		const [sms] = await Promise.all([