title: Unable to run tests in Visual Studio
body: <p>I created a solution with 2 projects, <code>FSharpCalled</code> (which contains a method "disBonjour", transforming a string in another), an F# library,  and FSharpTest shown below : </p>
  
  <p><a href="https://i.stack.imgur.com/RAMp2.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/RAMp2.png" alt="enter image description here"></a></p>
  
  <p>Here's FSharpCalled :</p>
  
  <p><a href="https://i.stack.imgur.com/czcjY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/czcjY.png" alt="here"></a></p>
  
  <p>The problem is that I can't run the tests; as shown in the first screenshot, I get an error message saying the "principal module is empty, so nothing will happen at execution".</p>
  
  <p>I tried to modify some properties but without success.</p>
  
  <p>EDIT:</p>
  
  <p>here's the result... damn!</p>
  
  <p><a href="https://i.stack.imgur.com/7nTS5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7nTS5.png" alt="enter image description here"></a></p>