title: Looking for a recommended Unit Test design approach when I need to process complex and large XML files
body: <p>I am using Visual Studio 2017 Unit Test Projects.</p>
  
  <p>I have an application that reads complex XML files, and do some processing based on XPATH queries in their data. I need to build a series of unit tests for my application. Below two options come to my mind:</p>
  
  <p><strong>Option #1</strong>: Include a few selected XML files as part of the Unit Test Project. </p>
  
  <p>Create unit tests that reads the files, and tests specific scenarios.
  This is the most intuitive and easiest option for me. Because I can include many complex scenarios in my selected XML files update them as required, then build all the required unit tests.</p>
  
  <p><strong>Option #2</strong>: Create mock classes that provide specific XML data scenarios</p>
  
  <p>I need to create a few mock classes that provide specific XML data scenarios.  The application needs to be updated such that it gets the data through classes in an IoC container.</p>
  
  <p>To me, Option#1 is quite simple, but I wanted to get more information on the Option#2 </p>
  
  <p><strong>Question</strong>:
  Are above two options aligned with Unit Test design best practices? What is the most optimal Unit Test design for my senatio?</p>