title: Lambda expression as inline data in xUnit
body: <p>I'm pretty new to xUnit and here's what I'd like to achieve:</p>
  
  <pre><code>[Theory]
  [InlineData((Config y) =&gt; y.Param1)]
  [InlineData((Config y) =&gt; y.Param2)]
  public void HasConfiguration(Func&lt;Config, string&gt; item)
  {
      var configuration = serviceProvider.GetService&lt;GenericConfig&gt;();
      var x = item(configuration.Config1); // Config1 is of type Config
  
      Assert.True(!string.IsNullOrEmpty(x));            
  }
  </code></pre>
  
  <p>Basically, I have a <em>GenericConfig</em> object which contains <em>Config</em> and other kind of configurations, but I need to check that every single parameter is valid. Since they're all string, I wanted to simplify using <em>[InlineData]</em> attribute instead of writing N equals tests.</p>
  
  <p>Unfortunately the error I'm getting is "Cannot convert lambda expression to type 'object[]' because it's not a delegate type", which is pretty much clear.</p>
  
  <p>Do you have any idea on how to overcome this?</p>