title: NUnit parameterized tests with datetime
body: <p>Is it not possible with NUnit to go the following?</p>
  <pre class="lang-cs prettyprint-override"><code>[TestCase(new DateTime(2010,7,8), true)]
  public void My Test(DateTime startdate, bool expectedResult)
  {
      ...
  }
  </code></pre>
  <p>I really want to put a <code>datetime</code> in there, but it doesn't seem to like it. The error is:</p>
  <blockquote>
  <p>An attribute argument must be a constant expression, typeof expression
  or array creation expression of an attribute parameter type</p>
  </blockquote>
  <p>Some documentation I read seems to suggest you should be able to, but I can't find any examples.</p>