[testing] Write screenshots to disk if rdb is not available

Bug: b:333423685
Change-Id: I7d866814d17860e0704d1fda12f4183d9bfdab56
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/5442779
Commit-Queue: Philip Pfaffe <pfaffe@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Reviewed-by: Eric Leese <leese@chromium.org>

test/shared/mocha-extensions.ts

@@ -32,16 +32,6 @@ export async function takeScreenshots(): Promise<{target?: string, frontend?: st
   }
 }
 
-async function takeScreenshotsForError(): Promise<{target?: string, frontend?: string}> {
-  if (getEnvVar('LUCI_CONTEXT')) {
-    const screenshots = await takeScreenshots();
-    console.error('Screenshots will be uploaded to luci-milo invocation.');
-    return screenshots;
-  }
-  console.error('Screenshots skipped because we are not running under rdb; did you run `npm run auto-e2etest-rdb`?');
-  return {};
-}
-
 function wrapSuiteFunction(fn: (this: Mocha.Suite) => void) {
   return function(this: Mocha.Suite): void {
     const hookCreationHook = (hook: Mocha.Hook) => {
@@ -144,7 +134,7 @@ async function timeoutHook(this: Mocha.Runnable, done: Mocha.Done|undefined, err
     }
   }
   if (err && !getEnvVar('DEBUG_TEST') && !(err instanceof ScreenshotError)) {
-    const {target, frontend} = await takeScreenshotsForError();
+    const {target, frontend} = await takeScreenshots();
     err = ScreenshotError.fromBase64Images(err, target, frontend);
   }
   if (done) {
@@ -227,7 +217,7 @@ function wrapMochaCall(
       async function onError(this: unknown, err?: unknown) {
         const isTimeoutError = err instanceof Error && err.message?.includes(TIMEOUT_ERROR_MESSAGE);
         if (err && !getEnvVar('DEBUG_TEST') && !(err instanceof ScreenshotError) && !isTimeoutError) {
-          const {target, frontend} = await takeScreenshotsForError();
+          const {target, frontend} = await takeScreenshots();
           err = ScreenshotError.fromBase64Images(err, target, frontend);
         }
         done.call(this, err);

test/shared/mocha-resultsdb-reporter.ts

@@ -2,7 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import * as fs from 'fs';
 import * as Mocha from 'mocha';
+import * as path from 'path';
 
 import {
   ScreenshotError,
@@ -49,6 +51,12 @@ class ResultsDbReporter extends Mocha.reporters.Spec {
   // the rest of the HTML formatting (e.g. <pre> and </pre>).
   static readonly SUMMARY_LENGTH_CUTOFF = 3985;
   private suitePrefix?: string;
+  htmlResult: fs.WriteStream|undefined;
+
+  localResultsPath() {
+    return !ResultsDb.available() && this.suitePrefix ? path.join(__dirname, '..', this.suitePrefix, 'results.html') :
+                                                        undefined;
+  }
 
   constructor(runner: Mocha.Runner, options?: Mocha.MochaOptions) {
     super(runner, options);
@@ -56,6 +64,12 @@ class ResultsDbReporter extends Mocha.reporters.Spec {
     // BUT, every module.exports is forwarded onto the options object.
     this.suitePrefix = (options as {suiteName: string} | undefined)?.suiteName;
 
+    const localResults = this.localResultsPath();
+
+    if (localResults) {
+      this.htmlResult = fs.createWriteStream(localResults, {});
+    }
+
     runner.on(EVENT_TEST_PASS, this.onTestPass.bind(this));
     runner.on(EVENT_TEST_FAIL, this.onTestFail.bind(this));
     runner.on(EVENT_TEST_RETRY, this.onTestFail.bind(this));
@@ -78,6 +92,16 @@ class ResultsDbReporter extends Mocha.reporters.Spec {
     } else {
       testResult.summaryHtml = `<pre>${getErrorMessage(error).slice(0, ResultsDbReporter.SUMMARY_LENGTH_CUTOFF)}</pre>`;
     }
+    if (this.htmlResult) {
+      this.htmlResult.write(testResult.summaryHtml);
+      if (testResult.artifacts) {
+        for (const screenshot in testResult.artifacts) {
+          this.htmlResult.write(`<details><summary>${screenshot} screenshot:</summary><p><img src="${
+              testResult.artifacts[screenshot].filePath}"></img></p></details>`);
+        }
+      }
+      this.htmlResult.write('<hr>');
+    }
     ResultsDb.sendTestResult(testResult);
   }
 
@@ -98,6 +122,14 @@ class ResultsDbReporter extends Mocha.reporters.Spec {
       tags: [{key: 'run', 'value': String(testRetry.currentRetry() + 1)}],
     };
   }
+
+  override epilogue() {
+    super.epilogue();
+    const localResults = this.localResultsPath();
+    if (this.failures.length > 0 && localResults) {
+      console.error(`Results have been written to file://${localResults}`);
+    }
+  }
 }
 
 exports = module.exports = ResultsDbReporter;

test/shared/resultsdb.ts

@@ -64,6 +64,11 @@ function getSinkData(): SinkData {
   return resolvedSinkData;
 }
 
+export function available() {
+  const sinkData = getSinkData();
+  return sinkData.url !== undefined;
+}
+
 // Call at the end of a test suite. Will send all `TestResult`s collected via
 // `recordTestResult` to the ResultSink endpoint (only if available).
 export function sendTestResult(results: TestResult): void {