Bug 1407945: Add a test for the tooltip in RDM. r=pbro

Differential Revision: https://phabricator.services.mozilla.com/D38827

--HG--
extra : moz-landing-system : lando

devtools/client/responsive.html/test/browser/browser.ini

@@ -76,6 +76,7 @@ skip-if = fission
 skip-if = os == "linux" || os == "mac" # Bug 1498336
 [browser_toolbox_swap_browsers.js]
 [browser_toolbox_swap_inspector.js]
+[browser_tooltip.js]
 [browser_touch_device.js]
 [browser_touch_does_not_trigger_hover_states.js]
 [browser_touch_simulation.js]

devtools/client/responsive.html/test/browser/browser_tooltip.js

@@ -0,0 +1,27 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_CONTENT = `<h1 title="test title">test h1</h1>`;
+const TEST_URL = `data:text/html;charset=utf-8,${ encodeURIComponent(TEST_CONTENT) }`;
+
+// Test for the tooltip coordinate on the browsing document in RDM.
+
+addRDMTask(TEST_URL, async ({ ui }) => {
+  info("Show a tooltip");
+  await spawnViewportTask(ui, {}, () => {
+    const target = content.document.querySelector("h1");
+    const { x: targetX, y: targetY } = target.getClientRects()[0];
+    content.windowUtils.sendMouseEvent("mouseover", targetX, targetY, 0, 0, 0);
+    content.windowUtils.sendMouseEvent("mousemove", targetX + 1, targetY, 0, 0, 0);
+  });
+
+  info("Wait for showing the tooltip");
+  const tooltip =
+    ui.browserWindow.gBrowser.ownerDocument.getElementById("remoteBrowserTooltip");
+  await waitUntil(() => tooltip.state === "open");
+
+  info("Test the X coordinate of the tooltip");
+  isnot(tooltip.screenX, 0, "The X coordinate of tooltip should not be 0");
+});