notif: Separate ids in pm_users for group PMs with ',' instead of ', '.

', ' would have been handled correctly, but seemingly by accident;
in getNarrowFromNotificationData, pm_users was split on ',' to give
['1', ' 2', ' 3'] (note the spaces), then + was used on elements of
that array, as in +idStrs[i], to convert to a number.

Also, replace the confusing + syntax with parseInt.

android/app/src/main/java/com/zulipmobile/notifications/FcmMessage.kt

@@ -51,7 +51,7 @@ sealed class Recipient {
      * pmUsers: the user IDs of all users in the conversation.
      */
     data class GroupPm(val pmUsers: Set<Int>) : Recipient() {
-        fun getPmUsersString() = pmUsers.sorted().joinToString { it.toString() }
+        fun getPmUsersString() = pmUsers.sorted().joinToString(separator=",") { it.toString() }
     }
 
     /** A stream message. */

android/app/src/test/java/com/zulipmobile/notifications/FcmMessageTest.kt

@@ -55,13 +55,13 @@ class FcmMessageTest : FcmMessageTestBase() {
 class RecipientTest : FcmMessageTestBase() {
     @Test
     fun `GroupPm#getPmUsersString gives the correct string`() {
-        expect.that(Recipient.GroupPm(pmUsers = setOf(123, 234, 345)).getPmUsersString())
-            .isEqualTo("123, 234, 345")
+        expect.that(Recipient.GroupPm(pmUsers = setOf(123,234,345)).getPmUsersString())
+            .isEqualTo("123,234,345")
     }
     @Test
     fun `GroupPm#getPmUsersString correctly reorders user ids`() {
-        expect.that(Recipient.GroupPm(pmUsers = setOf(234, 123, 23, 345)).getPmUsersString())
-            .isEqualTo("23, 123, 234, 345")
+        expect.that(Recipient.GroupPm(pmUsers = setOf(234,123,23,345)).getPmUsersString())
+            .isEqualTo("23,123,234,345")
     }
 }
 

src/notification/__tests__/notification-test.js

@@ -30,7 +30,7 @@ describe('getNarrowFromNotificationData', () => {
   test('on notification for a group message returns a group narrow', () => {
     const notification = {
       recipient_type: 'private',
-      pm_users: '1, 2, 4',
+      pm_users: '1,2,4',
     };
     const usersById = new Map([
       [1, { email: '[email protected]' }],
@@ -47,7 +47,7 @@ describe('getNarrowFromNotificationData', () => {
   test('do not throw when users are not found; return null', () => {
     const notification = {
       recipient_type: 'private',
-      pm_users: '1, 2, 4',
+      pm_users: '1,2,4',
     };
     const usersById = new Map();
 

src/notification/index.js

@@ -121,7 +121,8 @@ export const getNarrowFromNotificationData = (
   const emails = [];
   const idStrs = data.pm_users.split(',');
   for (let i = 0; i < idStrs.length; ++i) {
-    const user = usersById.get(+idStrs[i]);
+    const id = parseInt(idStrs[i], 10);
+    const user = usersById.get(id);
     if (!user) {
       return null;
     }