From e40c4e6b7ce796613d8bde9e4edc91e2c24a26f4 Mon Sep 17 00:00:00 2001
From: biomedia-thomas <github@biomedia.nl>
Date: Tue, 16 Oct 2018 16:29:24 +0200
Subject: [PATCH] Use at least one worker by default (fixes #7181)

---
 packages/jest-worker/src/index.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/jest-worker/src/index.js b/packages/jest-worker/src/index.js
index 0b787d7e57b6..0cb636c2fc6c 100644
--- a/packages/jest-worker/src/index.js
+++ b/packages/jest-worker/src/index.js
@@ -57,7 +57,7 @@ export default class {
   _offset: number;
 
   constructor(workerPath: string, options?: FarmOptions = {}) {
-    const numWorkers = options.numWorkers || os.cpus().length - 1;
+    const numWorkers = options.numWorkers || Math.max(os.cpus().length - 1, 1);
     const workers = new Array(numWorkers);
     const stdout = mergeStream();
     const stderr = mergeStream();