From 48dc466eea3d4a509a74693d86d2e29b284ba346 Mon Sep 17 00:00:00 2001
From: Paul Lewis <aerotwist@chromium.org>
Date: Wed, 1 Apr 2020 10:48:19 +0100
Subject: [PATCH] [e2e] Fix selection after delete

Discovered a race condition when running e2e in SLOWMO. This CL fixes
the race condition by ensuring that the old content is definitely
grabbed before the backspace key is pressed.

Change-Id: I6f39f18b8352ed03a1b6e4c067a2e526589b4ace
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2130789
Commit-Queue: Paul Lewis <aerotwist@chromium.org>
Reviewed-by: Jack Franklin <jacktfranklin@chromium.org>
---
 test/e2e/elements/selection-after-delete.ts | 9 ++++-----
 test/e2e/helpers/elements-helpers.ts        | 5 ++---
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/test/e2e/elements/selection-after-delete.ts b/test/e2e/elements/selection-after-delete.ts
index 6f2ad90254..2e8e04fac5 100644
--- a/test/e2e/elements/selection-after-delete.ts
+++ b/test/e2e/elements/selection-after-delete.ts
@@ -5,14 +5,14 @@
 import {describe, it} from 'mocha';
 
 import {click, getBrowserAndPages, resetPages, resourcesPath, waitFor, waitForElementWithTextContent} from '../../shared/helper.js';
-import {assertContentOfSelectedElementsNode, expandSelectedNodeRecursively, waitForSelectedNodeChange} from '../helpers/elements-helpers.js';
+import {assertContentOfSelectedElementsNode, expandSelectedNodeRecursively, getContentOfSelectedNode, waitForSelectedNodeChange} from '../helpers/elements-helpers.js';
 
 describe('The Elements tab', async () => {
   beforeEach(async () => {
     await resetPages();
   });
 
-  it('can delete stuff', async () => {
+  it('can delete elements in the tree', async () => {
     const {target, frontend} = getBrowserAndPages();
 
     await target.goto(`${resourcesPath}/elements/selection-after-delete.html`);
@@ -40,10 +40,9 @@ describe('The Elements tab', async () => {
     do {
       const nextVal = expected.shift() || '';
 
-      // Start watching for the node change before hitting backspace.
-      const elementChanged = waitForSelectedNodeChange();
+      const initialValue = await getContentOfSelectedNode();
       await frontend.keyboard.press('Backspace');
-      await elementChanged;
+      await waitForSelectedNodeChange(initialValue);
 
       await assertContentOfSelectedElementsNode(nextVal);
     } while (expected.length);
diff --git a/test/e2e/helpers/elements-helpers.ts b/test/e2e/helpers/elements-helpers.ts
index 13e1fc21dd..1887031cb6 100644
--- a/test/e2e/helpers/elements-helpers.ts
+++ b/test/e2e/helpers/elements-helpers.ts
@@ -24,16 +24,15 @@ export const getContentOfSelectedNode = async () => {
   return await selectedNode.evaluate(node => node.textContent);
 };
 
-export const waitForSelectedNodeChange = async (maxTotalTimeout = 1000) => {
+export const waitForSelectedNodeChange = async (initialValue: string, maxTotalTimeout = 1000) => {
   if (maxTotalTimeout === 0) {
     maxTotalTimeout = Number.POSITIVE_INFINITY;
   }
 
   const start = performance.now();
-  const initialNodeContent = await getContentOfSelectedNode();
   do {
     const currentContent = await getContentOfSelectedNode();
-    if (currentContent !== initialNodeContent) {
+    if (currentContent !== initialValue) {
       return currentContent;
     }