diff --git a/chrome/content/zotero/tools/testTranslators/translatorTester.js b/chrome/content/zotero/tools/testTranslators/translatorTester.js
index cf19c10308..7520812640 100644
--- a/chrome/content/zotero/tools/testTranslators/translatorTester.js
+++ b/chrome/content/zotero/tools/testTranslators/translatorTester.js
@@ -256,6 +256,8 @@ Zotero_TranslatorTester._sanitizeItem = function(item, testItem, keepValidFields
 			var attachment = item.attachments[i];
 			if(attachment.document) {
 				delete attachment.document;
+				// Mirror connector/server itemDone() behavior from translate.js
+				attachment.mimeType = 'text/html';
 			}
 			
 			if(attachment.url) {