Log cas-viewer url to screenshot html file

Code predicts the cas-viewer url where the screenshots file
will be uploaded so that the link can be copied from the test log.

Bug: None
Change-Id: Ia5739f7915c2ab657ab8085ce20496327f552684
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/4813643
Commit-Queue: Eric Leese <leese@chromium.org>
Reviewed-by: Almothana Athamneh <almuthanna@chromium.org>

test/conductor/mocha_hooks.ts

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import * as Crypto from 'crypto';
 import * as fs from 'fs';
 import {createCoverageMap, createFileCoverage} from 'istanbul-lib-coverage';
 import * as report from 'istanbul-lib-report';
@@ -62,6 +63,18 @@ export function mochaGlobalTeardown() {
   stopServer();
 }
 
+function logScreenshotFileUrl() {
+  const screenshotFile = process.env.HTML_OUTPUT_FILE;
+  if (screenshotFile) {
+    const hash = Crypto.createHash('sha256');
+    const contents = fs.readFileSync(screenshotFile);
+    hash.update(contents);
+    console.error(
+        `If running on bots, screenshots can be downloaded from: https://cas-viewer.appspot.com/projects/chromium-swarm/instances/default_instance/blobs/${
+            hash.digest('hex')}/${contents.byteLength}?filename=screenshots.html`);
+  }
+}
+
 const testSuiteCoverageMap = createCoverageMap();
 
 const testsRunWithCoverageEnvSet = Boolean(process.env.COVERAGE || process.env.COVERAGE_FOLDERS);
@@ -88,6 +101,7 @@ export const mochaHooks = {
   // In parallel mode, run after all tests end, for each file.
   afterAll: async function(this: Mocha.Suite) {
     await postFileTeardown();
+    logScreenshotFileUrl();
 
     if (!SHOULD_GATHER_COVERAGE_INFORMATION) {
       return;

test/shared/mocha-extensions.ts

@@ -12,7 +12,7 @@ import {AsyncScope} from './async-scope.js';
 import {getEnvVar} from './config.js';
 import {platform, type Platform, stepDescription} from './helper.js';
 
-export {beforeEach} from 'mocha';
+export {after, beforeEach} from 'mocha';
 
 let didInitializeHtmlOutputFile = false;