fix broken test

Signal/test/ViewControllers/ConversationViewItemTest.m

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 #import "ConversationViewItem.h"
@@ -65,6 +65,7 @@
     OWSAssertDebug([[NSFileManager defaultManager] fileExistsAtPath:filePath]);
 
     DataSource *dataSource = [DataSourcePath dataSourceWithFilePath:filePath shouldDeleteOnDeallocation:NO];
+    dataSource.sourceFilename = filename;
     TSAttachmentStream *attachment = [AttachmentStreamFactory createWithContentType:mimeType dataSource:dataSource];
 
     TSOutgoingMessage *message =

SignalServiceKit/src/TestUtils/Factories.swift

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 import Foundation
@@ -391,6 +391,7 @@ class AttachmentStreamFactory: NSObject, Factory {
         let factory = AttachmentStreamFactory()
         factory.contentTypeBuilder = { return contentType }
         factory.byteCountBuilder = { return UInt32(dataSource.dataLength()) }
+        factory.sourceFilenameBuilder = { return dataSource.sourceFilename ?? "fake-filename.dat" }
 
         let attachmentStream = factory.build(transaction: transaction)
         dataSource.write(toPath: attachmentStream.originalFilePath!)