Add UI tests

src/spec/scenarios/showNumericPlot.ts

@@ -0,0 +1,12 @@
+import { clickOn, sleep, writeText, expandTopic } from '../util'
+import { Browser } from 'webdriverio'
+
+export async function showNumericPlot(browser: Browser<void>) {
+  await expandTopic('livingroom/temperature', browser)
+
+  const messageHistory = await browser.$('//span/*[contains(text(), "History")]')
+  await clickOn(messageHistory, browser, 1)
+
+  await sleep(1000)
+  await expandTopic('livingroom/humidity', browser)
+}