tests: Switch to explicit chain vs implicit queue

tests/page.js

@@ -231,14 +231,16 @@ module.exports = function Page(browser) {
 
 	this.enterItem = function (itemText) {
 		var self = this;
-		browser.wait(function () {
-			var textField = self.getItemInputField();
-			textField.sendKeys(itemText, webdriver.Key.ENTER);
 
+		browser.wait(function () {
+			return self.getItemInputField().then(function (textField) {
+				return textField.sendKeys(itemText, webdriver.Key.ENTER);
+			}).then(function () {
 				return self.getVisibleLabelText()
 					.then(function (labels) {
 						return labels.indexOf(itemText.trim()) !== -1;
 					});
+			});
 		}, 5000);
 	};