While trying to create unit tests for view models (using the Model-View-ViewModel pattern), I came across a problem while trying to execute unit tests from NUnit. The error I recevied was:

The calling thread must be STA, because many UI components require this.

A quick search on Google yielded an answer.

However, the configuration file in the post was incorrect and was noted by a commentor. For expediency, I have included the correct configuration text below:

<configSections>
   <sectionGroup name="NUnit">
      <section type="System.Configuration.NameValueSectionHandler" name="TestRunner"></section>
   </sectionGroup>
</configSections>

<NUnit>
   <TestRunner>
      <add value="STA" key="ApartmentState"></add>
   </TestRunner>
</NUnit>