title: Override Standard Assert Messaging in Pytest Assert
body: <p>I'm using Pytest to test some SQL queries my team runs programmatically over time.</p>
  
  <p>My SQL queries are lists of JSONs - one JSON corresponds to one row of data.</p>
  
  <p>I've got a function that diffs the JSON key:value pairs so that we can point to exactly which values are different for a given row.  Ideally, I'd output a list of these diffs <em>instead</em> of the standard output of an assert statement, which ends up looking clunky and not-very-useful for the end user.</p>