title: How to guarantee corner cases in property based testing
body: <p>Recently, I'm quite excited when reading about the idea of property based testing. </p>
  
  <p>But I have 1 question that I still cannot find the answer anywhere:</p>
  
  <p><strong>How can property based testing ensures that it will test the corner cases every time?</strong></p>
  
  <p>To be more specific, let say I'm using <a href="https://www.scalacheck.org/" rel="nofollow noreferrer">ScalaCheck</a> to test my division function:</p>
  
  <pre><code>def divide(a: Int, b: Int): Int
  </code></pre>
  
  <p>As the test cases will be generated randomly, how can I be sure that ScalaCheck will check the case where <code>b = 0</code> every time?</p>