diff --git a/scripts/testall.js b/scripts/testall.js
index 1f33a7f70d5..139aa90e519 100644
--- a/scripts/testall.js
+++ b/scripts/testall.js
@@ -2,6 +2,7 @@ const fs = require('fs')
 const path = require('path')
 const spawn = require('child_process').spawn
 
+const projectRoot = path.normalize(path.join(__dirname, '..'))
 const outputLog = path.join(projectRoot, '.test-failures.log')
 
 // Start with a fresh output log on each run.