Merge pull request #963 from nunit/nunitlite

Adding a paragraph about the startupobject,

docs/articles/nunit/running-tests/NUnitLite-Runner.md

@@ -57,3 +57,18 @@ installed and referenced for you.
 As seen in the following screen shot, the output from an NUnitLite run is quite similar to that from the console runner.
 
 ![Screenshot of NUnitLite](~/images/nunitlite-mock.png)
+
+## Tips
+
+### Testing an executable application
+
+When testing an executable application, you can use the NUnitLite runner to execute your tests.
+However, this approach will result in having two Main methods in your application. To resolve this,
+you need to specify which Main method to use — specifically, the Main method from the test project.
+You do this by stating which class contains this method.
+
+You do this by adding a `StartupObject` to your project file:
+
+```xml
+  <StartupObject>TestProject.Program</StartupObject>
+```