title: Jest test doesn't create the files the normal program would
body: <p>I'm using node and puppeteer to load a page, get its content and then create a screenshot if it. At the end of the run function I have the following lines</p>
  
  <pre><code>var content = fs.writeFileSync(outputFilePath, processedContent);
  var screenshot = page.screenshot({path: '../output/whatever.png', fullPage:true})
  browser.close();
  </code></pre>
  
  <p>This works when running the node app. For testing I am using JEST
  And when trying to run the JEST test that checks for the screenshot:</p>
  
  <pre><code>it('Run should take a screenshot', async() =&gt; {
      const runResult = await run();
      const screenshot = fs.readFileSync('/app/output/whatever.png');
      expect(screenshot).toBeTruthy();
  })
  </code></pre>
  
  <p>I get the following error ENOENT: no such file or directory, open '/app/output/whatever.png'</p>
  
  <p>I'm having a hard time understanding why in the normal app flow the program creates the files when running but in the tests it doesn't. As additional info the entire thing runs in a Docker container</p>