title: Detox build with Expo - "Error: Could not find build script in detox.configurations["ios.sim"].build"
body: <p><strong>Goal:</strong>
  I would like to be able to run detox tests for an expo app with Travis.</p>
  
  <p>I created a bare-bones expo app that successfully runs a single detox test on my local machine. After pushing to git and running on Travis, all dependencies install successfully and then the Travis build scripts fail with the following error.</p>
  
  <p><strong>Error:</strong>
  <code>Error: Could not find build script in detox.configurations["ios.sim"].build</code></p>
  
  <p><strong>Issue:</strong>
  It looks like the issue occurs because there isn't a "build" entry in the "ios.sim" configuration for "detox" in <code>package.json</code>. For a non-expo React Native project with detox, the corresponding <code>.xcodeproject</code> or <code>.xxworkspace</code> can be built directly. Expo doesn't have a <code>.xcodeproject</code> or <code>.xcworkspace</code> - what to put for the "build" configuration for an Expo project? While there is an Exponent.the app provided by the expo to run tests with detox, I don't see any <code>.xcodeproject or .xcworkspace</code> to build with.</p>
  
  <p><strong>Repro steps:</strong></p>
  
  <ul>
  <li>Clone git@github.com:bryanboyko/expo-detox-travis-3.git</li>
  <li><code>cd expo-detox-travis-3</code></li>
  <li><code>npm install</code></li>
  <li><code>./setup.sh</code></li>
  <li><code>detox test</code></li>
  <li>push to a new branch and create a PR to see travis build</li>
  </ul>
  
  <p><strong>Travis failure log:</strong>
  <a href="https://travis-ci.com/bryanboyko/expo-detox-travis-3/builds/151879107" rel="nofollow noreferrer">https://travis-ci.com/bryanboyko/expo-detox-travis-3/builds/151879107</a></p>