add test for joining preexisting room

tests/join_room.js

@@ -0,0 +1,35 @@
+/*
+Copyright 2018 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+const helpers = require('../helpers');
+const assert = require('assert');
+
+module.exports = async function join_room(page, room_name) {
+  //TODO: brittle selector
+  const directory_button = await helpers.wait_and_query_selector(page, '.mx_RoleButton[aria-label="Room directory"]');
+  await directory_button.click();
+
+  const room_input = await helpers.wait_and_query_selector(page, '.mx_DirectorySearchBox_input');
+  await helpers.replace_input_text(room_input, room_name);
+
+  const first_room_label = await helpers.wait_and_query_selector(page, '.mx_RoomDirectory_table .mx_RoomDirectory_name:first-child');
+  await first_room_label.click();
+
+  const join_link = await helpers.wait_and_query_selector(page, '.mx_RoomPreviewBar_join_text a');
+  await join_link.click();
+
+  await page.waitForSelector('.mx_MessageComposer');
+}