diff --git a/script/lib/utils.js b/script/lib/utils.js
index 2958c50e9b84..e3c7d483f009 100644
--- a/script/lib/utils.js
+++ b/script/lib/utils.js
@@ -4,13 +4,13 @@ const path = require('path')
 
 const ELECTRON_DIR = path.resolve(__dirname, '..', '..')
 const SRC_DIR = path.resolve(ELECTRON_DIR, '..')
-const OUT_DIR = process.env.ELECTRON_OUT_DIR || 'Debug'
 
 require('colors')
 const pass = '\u2713'.green
 const fail = '\u2717'.red
 
 function getElectronExec () {
+  const OUT_DIR = getOutDir()
   switch (process.platform) {
     case 'darwin':
       return `out/${OUT_DIR}/Electron.app/Contents/MacOS/Electron`
@@ -23,6 +23,20 @@ function getElectronExec () {
   }
 }
 
+function getOutDir (shouldLog) {
+  if (process.env.ELECTRON_OUT_DIR) {
+    return process.env.ELECTRON_OUT_DIR
+  } else {
+    for (const buildType of ['Debug', 'Testing', 'Release']) {
+      const outPath = path.resolve(SRC_DIR, 'out', buildType)
+      if (fs.existsSync(outPath)) {
+        if (shouldLog) console.log(`OUT_DIR is: ${buildType}`)
+        return buildType
+      }
+    }
+  }
+}
+
 function getAbsoluteElectronExec () {
   return path.resolve(SRC_DIR, getElectronExec())
 }
@@ -62,8 +76,8 @@ async function getCurrentBranch (gitDir) {
 module.exports = {
   getCurrentBranch,
   getElectronExec,
+  getOutDir,
   getAbsoluteElectronExec,
   ELECTRON_DIR,
-  OUT_DIR,
   SRC_DIR
 }
diff --git a/script/nan-spec-runner.js b/script/nan-spec-runner.js
index b5e40e288d3e..5230e4e00f37 100644
--- a/script/nan-spec-runner.js
+++ b/script/nan-spec-runner.js
@@ -14,7 +14,7 @@ if (!process.mainModule) {
 }
 
 async function main () {
-  const nodeDir = path.resolve(BASE, `out/${utils.OUT_DIR}/gen/node_headers`)
+  const nodeDir = path.resolve(BASE, `out/${utils.getOutDir(true)}/gen/node_headers`)
   const env = Object.assign({}, process.env, {
     npm_config_nodedir: nodeDir,
     npm_config_msvs_version: '2017',
diff --git a/script/spec-runner.js b/script/spec-runner.js
index abf54745152e..80e00adaf0b9 100755
--- a/script/spec-runner.js
+++ b/script/spec-runner.js
@@ -142,7 +142,7 @@ async function runMainProcessElectronTests () {
 }
 
 async function installSpecModules () {
-  const nodeDir = path.resolve(BASE, `out/${utils.OUT_DIR}/gen/node_headers`)
+  const nodeDir = path.resolve(BASE, `out/${utils.getOutDir(true)}/gen/node_headers`)
   const env = Object.assign({}, process.env, {
     npm_config_nodedir: nodeDir,
     npm_config_msvs_version: '2017'