title: How to use CTest to check difference between two files?
body: <p>I'm trying to create some integrated tests for some legacy software. The current way to do testing is to run the code with known inputs and <em>manually</em> compare the output to the known output. </p>
  
  <p>I'd like to automate this process, since I'm already using CMake I would like to do this with CTest. I have about two dozen inputs/outputs that I need to check. </p>
  
  <p><strong>What is the right way to do this?</strong> I only have a moderate amount of experience with CMake and even less with CTest.</p>