From 2dc73ad2a76e17de15c298ec970487aae3a65249 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Sat, 13 Jun 2026 22:54:33 +0200
Subject: [PATCH] Collect coverage data from all workers when closing
 integration-tests

The "Merge PDF" integration-tests will (indirectly) invoke `PDFViewerApplication.open` as part of loading the new PDF document, which will end up creating a new `PDFWorker` instance.
Currently worker coverage is only collected at the end of each integration-test, which means that in these cases we miss the coverage data from any "previous" workers.
---
 test/integration/test_utils.mjs | 19 ++-----------------
 web/app.js                      | 17 +++++++++++++++++
 2 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/test/integration/test_utils.mjs b/test/integration/test_utils.mjs
index 67796e420..8aab655d6 100644
--- a/test/integration/test_utils.mjs
+++ b/test/integration/test_utils.mjs
@@ -151,19 +151,6 @@ function closePages(pages) {
 
 async function closeSinglePage(page) {
   const coverage = await page.evaluate(async () => {
-    // Collect coverage data from the worker before the document is closed.
-    let workerCoverage = null;
-    const handler =
-      window.PDFViewerApplication.pdfDocument?._transport?.messageHandler;
-    if (handler) {
-      try {
-        workerCoverage = await handler.sendWithPromise(
-          "GetWorkerCoverage",
-          null
-        );
-      } catch {}
-    }
-
     // Close the viewer gracefully, and clear local storage to avoid state
     // leaking from one test to another.
     await window.PDFViewerApplication.testingClose();
@@ -175,16 +162,14 @@ async function closeSinglePage(page) {
     // logic kicks in (see https://github.com/puppeteer/puppeteer/issues/2427).
     return {
       page: window.__coverage__ ? JSON.stringify(window.__coverage__) : null,
-      worker: workerCoverage ? JSON.stringify(workerCoverage) : null,
+      workers: window.__worker_coverage__?.map(c => JSON.stringify(c)) ?? null,
     };
   });
 
   if (coverage.page) {
     mergeCoverageIntoGlobal(JSON.parse(coverage.page));
   }
-  if (coverage.worker) {
-    mergeCoverageIntoGlobal(JSON.parse(coverage.worker));
-  }
+  coverage.workers?.map(c => mergeCoverageIntoGlobal(JSON.parse(c)));
 
   await page.close({ runBeforeUnload: false });
 }
diff --git a/web/app.js b/web/app.js
index 52afe2be8..e3d9fb9fe 100644
--- a/web/app.js
+++ b/web/app.js
@@ -1165,6 +1165,23 @@ const PDFViewerApplication = {
         // Ignoring errors, to ensure that document closing won't break.
       }
     }
+
+    if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("COVERAGE")) {
+      // Collect coverage data from the worker before the document is closed.
+      //
+      // Note that `PDFViewerApplication.open` may be invoked multiple times
+      // during an integration-test (see e.g. the "Merge PDF" tests).
+      const handler = this.pdfDocument?._transport?.messageHandler;
+      if (handler) {
+        try {
+          const workerCoverage = await handler.sendWithPromise(
+            "GetWorkerCoverage",
+            null
+          );
+          (window.__worker_coverage__ ??= []).push(workerCoverage);
+        } catch {}
+      }
+    }
     const promises = [];
 
     promises.push(this.pdfLoadingTask.destroy());