diff --git a/src/translation/translate.js b/src/translation/translate.js
index 973637b..67ed34b 100644
--- a/src/translation/translate.js
+++ b/src/translation/translate.js
@@ -1113,7 +1113,7 @@ Zotero.Translate.Base.prototype = {
 				if(t) promises.push(t);
 			}
 			if(!promises.length) return Zotero.Promise.reject(new Error("getTranslators: no valid translators were set"));
-			potentialTranslators = Zotero.Promise.all(promises);
+			potentialTranslators = Zotero.Promise.all(promises).then(val => [val]);
 		} else {
 			potentialTranslators = this._getTranslatorsGetPotentialTranslators();
 		}
@@ -1720,6 +1720,16 @@ Zotero.Translate.Base.prototype = {
 		if (returnValue !== undefined) this._returnValue = returnValue;
 		this.decrementAsyncProcesses("Zotero.Translate#getTranslators");
 		
+		// If the translator started an async process in detect* (like loading another translator),
+		// wait for it in the promise we return
+		if (this._runningAsyncProcesses) {
+			return new Promise((resolve, reject) => {
+				this.setHandler('translators', () => resolve(this._returnValue));
+				this.setHandler('error', (_, err) => reject(err));
+			});
+		}
+		
+		// Otherwise, immediately return what detect* returned
 		return returnValue;
 	},
 	
@@ -1798,14 +1808,14 @@ Zotero.Translate.Base.prototype = {
 		}.bind(this);
 		
 		if (this.noWait) {
-			let codePromise = Zotero.Translators.getCodeForTranslator(translator);
+			let codePromise = this._translatorProvider.getCodeForTranslator(translator);
 			if (!codePromise.isResolved()) {
 				throw new Error("Code promise is not resolved in noWait mode");
 			}
 			parse(codePromise.value());
 		}
 		else {
-			return Zotero.Translators.getCodeForTranslator(translator).then(parse);
+			return this._translatorProvider.getCodeForTranslator(translator).then(parse);
 		}
 	}),
 	
diff --git a/testTranslators/translatorTester.js b/testTranslators/translatorTester.js
index 64bdaa9..9141a31 100644
--- a/testTranslators/translatorTester.js
+++ b/testTranslators/translatorTester.js
@@ -414,35 +414,41 @@ Zotero_TranslatorTester.prototype._runTestsRecursively = function(testDoneCallba
  * @param {Object} test - Test to execute
  * @param {Function} testDoneCallback - A callback to be executed when test is complete
  */
-Zotero_TranslatorTester.prototype.fetchPageAndRunTest = function (test, testDoneCallback) {
+Zotero_TranslatorTester.prototype.fetchPageAndRunTest = async function (test, testDoneCallback) {
 	// Scaffold
 	if (Zotero.isFx) {
-		let browser = Zotero.HTTP.loadDocuments(
-			test.url,
-			(doc) => {
-				if (test.defer) {
-					Zotero.debug("Waiting " + (Zotero_TranslatorTester.DEFER_DELAY / 1000)
-						+ " second(s) for page content to settle");
-				}
-				setTimeout(() => {
-					// Use cookies from document in translator HTTP requests
-					this._cookieSandbox = new Zotero.CookieSandbox(null, test.url, doc.cookie);
-					
-					this.runTest(test, doc, function (obj, test, status, message) {
-						Zotero.Browser.deleteHiddenBrowser(browser);
-						testDoneCallback(obj, test, status, message);
-					});
-				}, test.defer ? Zotero_TranslatorTester.DEFER_DELAY : 0);
-			},
-			null,
-			(e) => {
-				Zotero.Browser.deleteHiddenBrowser(browser);
-				testDoneCallback(this, test, "failed", "Translation failed to initialize: " + e);
-			},
-			true
-		);
-		browser.docShell.allowMetaRedirects = true;
-		return
+		const { HiddenBrowser } = ChromeUtils.import("chrome://zotero/content/HiddenBrowser.jsm");
+		const { RemoteTranslate } = ChromeUtils.import("chrome://zotero/content/RemoteTranslate.jsm");
+		let browser = await HiddenBrowser.create(test.url, {
+			requireSuccessfulStatus: true,
+			docShell: { allowMetaRedirects: true }
+		});
+		let translate = new RemoteTranslate();
+		try {
+			if (test.defer) {
+				Zotero.debug("Waiting " + (Zotero_TranslatorTester.DEFER_DELAY / 1000)
+					+ " second(s) for page content to settle");
+				await Zotero.Promise.delay(Zotero_TranslatorTester.DEFER_DELAY);
+			}
+			else {
+				// Wait just a bit for things to settle
+				await Zotero.Promise.delay(100);
+			}
+			
+			await translate.setBrowser(browser);
+			await translate.setTranslatorProvider(this.translatorProvider);
+			translate.setTranslator(this.translator);
+			translate.setHandler("debug", (_, obj) => this._debug(this, obj));
+			translate.setHandler("error", (_, err) => this._debug(this, err));
+			let { test: newTest, status, message } = await translate.runTest(test);
+			translate.dispose();
+			testDoneCallback(this, newTest, status, message);
+		}
+		finally {
+			HiddenBrowser.destroy(browser);
+			translate.dispose();
+		}
+		return;
 	}
 	
 	if (typeof process === 'object' && process + '' === '[object process]'){
@@ -609,6 +615,11 @@ Zotero_TranslatorTester.prototype._checkResult = function(test, translate, retur
 		testDoneCallback(this, test, "failed", "Translation failed; examine debug output for errors");
 		return;
 	}
+
+	// Save items. This makes it easier to correct tests automatically.
+	test.itemsReturned = test.items === "multiple"
+		? "multiple"
+		: translate.newItems.map(item => Zotero_TranslatorTester._sanitizeItem(item));
 	
 	if(!translate.newItems.length) {
 		testDoneCallback(this, test, "failed", "Translation failed: no items returned");
@@ -629,14 +640,6 @@ Zotero_TranslatorTester.prototype._checkResult = function(test, translate, retur
 				// Show diff
 				this._debug(this, "TranslatorTester: Data mismatch detected:");
 				this._debug(this, Zotero_TranslatorTester._generateDiff(testItem, translatedItem));
-				
-				// Save items. This makes it easier to correct tests automatically.
-				var m = translate.newItems.length;
-				test.itemsReturned = new Array(m);
-				for(var j=0; j<m; j++) {
-					test.itemsReturned[j] = Zotero_TranslatorTester._sanitizeItem(translate.newItems[i]);
-				}
-				
 				testDoneCallback(this, test, "unknown", "Item "+i+" does not match");
 				return;
 			}
@@ -663,7 +666,7 @@ Zotero_TranslatorTester.prototype.newTest = async function (doc, testReadyCallba
 	}
 	translate.setDocument(doc);
 	// Use cookies from document
-	if (doc.cookie) {
+	if (doc.cookie && Zotero.CookieSandbox) {
 		translate.setCookieSandbox(new Zotero.CookieSandbox(
 			null,
 			doc.location.href,