title: Use methods of one file in another file
body: <p>I am a beginner in C#. I have written some functions in File1.xaml.cs</p>
  
  <p>I have another tester file Test.xaml.cs in which I need to test the functions I wrote in File1.xaml.cs.</p>
  
  <p>How can I do that ? Both the files are under the same namespace.</p>