updateLastMessage: Use MessageController for latest data

test/models/conversations_test.js

@@ -0,0 +1,70 @@
+describe('Conversations', () => {
+  it('updates lastMessage even in race conditions with db', async () => {
+    // Creating a fake conversation
+    const conversation = new window.Whisper.Conversation({
+      id: '8c45efca-67a4-4026-b990-9537d5d1a08f',
+      e164: '+15551234567',
+      uuid: '2f2734aa-f69d-4c1c-98eb-50eb0fc512d7',
+      type: 'private',
+    });
+
+    const destinationE164 = '+15557654321';
+
+    // Creating a fake message
+    const now = Date.now();
+    let message = new window.Whisper.Message({
+      attachments: [],
+      body: 'bananas',
+      conversationId: conversation.id,
+      delivered: 1,
+      delivered_to: [destinationE164],
+      destination: destinationE164,
+      expirationStartTimestamp: now,
+      hasAttachments: 0,
+      hasFileAttachments: 0,
+      hasVisualMediaAttachments: 0,
+      id: 'd8f2b435-e2ef-46e0-8481-07e68af251c6',
+      received_at: now,
+      recipients: [destinationE164],
+      sent: true,
+      sent_at: now,
+      sent_to: [destinationE164],
+      timestamp: now,
+      type: 'outgoing',
+    });
+
+    // Saving to db and updating the convo's last message
+    await window.Signal.Data.saveMessage(message.attributes, {
+      forceSave: true,
+      Message: window.Whisper.Message,
+    });
+    message = window.MessageController.register(message.id, message);
+    await window.Signal.Data.saveConversation(conversation.attributes, {
+      Conversation: window.Whisper.Conversation,
+    });
+    await conversation.updateLastMessage();
+
+    // Should be set to bananas because that's the last message sent.
+    assert.strictEqual(conversation.get('lastMessage'), 'bananas');
+
+    // Erasing message contents (DOE)
+    message.set({
+      isErased: true,
+      body: '',
+      bodyRanges: undefined,
+      attachments: [],
+      quote: null,
+      contact: [],
+      sticker: null,
+      preview: [],
+    });
+
+    // Not saving the message to db on purpose
+    // to simulate that a save hasn't taken place yet.
+
+    // Updating convo's last message, should pick it up from memory
+    await conversation.updateLastMessage();
+
+    assert.strictEqual(conversation.get('lastMessage'), '');
+  });
+});