From 6897b2225ad3567c322913864ae97267beae4922 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Greg=20Berg=C3=A9?= <berge.greg@gmail.com>
Date: Thu, 15 Feb 2024 11:07:52 +0100
Subject: [PATCH] fix: fix `WORKERS_COUNT` not found (#578)

---
 packages/jest-environment-puppeteer/src/browsers.ts | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/packages/jest-environment-puppeteer/src/browsers.ts b/packages/jest-environment-puppeteer/src/browsers.ts
index c65e798f..f4743a75 100644
--- a/packages/jest-environment-puppeteer/src/browsers.ts
+++ b/packages/jest-environment-puppeteer/src/browsers.ts
@@ -80,14 +80,19 @@ export const startBrowsers = async ({
   config: JestPuppeteerConfig;
   jestConfig: JestConfig;
 }): Promise<Browser[]> => {
+  const workersCount = getWorkersCount(jestConfig);
+  saveWorkersCount(workersCount);
+
   if (config.connect?.browserWSEndpoint) {
+    if (workersCount > 1) {
+      throw new Error(
+        "Cannot use `connect.browserWSEndpoint` with multiple workers. Set Jest `maxWorkers` to 1.",
+      );
+    }
     saveWsEndpoints([config.connect.browserWSEndpoint]);
     return [];
   }
 
-  const workersCount = getWorkersCount(jestConfig);
-  saveWorkersCount(workersCount);
-
   const browsers = await Promise.all(
     Array.from({ length: workersCount }).map(() => openBrowser(config)),
   );