title: assertTrue() in pytest to assert empty lists
body: <p>Is there a way to use <code>assertTrue()</code> or <code>assertFalse()</code> like a function in pytest for python unittests?
  I have a function which returns a list of elements. If the list is empty the test needs to fail through assertion.</p>
  
  <p>Is there anything like below:</p>
  
  <pre><code>assertFalse(function_returns_list()), "the list is non empty, contains error elements"
  </code></pre>