title: postman testing on 'response body contains string' does not work
body: <p>To narrow down the problem, I change the response body into something as simple as one sentence as text/plain. </p>
  
  <pre><code>this is a test
  </code></pre>
  
  <p>However, the following very basic function still fails: </p>
  
  <pre><code>tests["Body matches string"] = responseBody.has("this");    
  </code></pre>
  
  <p>Ironically this test works:</p>
  
  <pre><code>tests["Body matches string"] = responseBody.has("t");    
  </code></pre>
  
  <p>I am using the latest postman v4.11.1. It looks like a fundamental defect for postman.</p>