title: POST date values in django testCase
body: <p>I am trying to write a test to sign up a user. I can't get the form to validate because I can't figure out how to submit a valid date to the form. Here is the offending code:</p>
  
  <pre><code>class AccountManagementTest(TestCase):
      def test_signup(self):
          response = self.client.post(reverse('register'), {
              'first_name': 'Gandalf', 
              'last_name': 'TheGrey', 
              'email': 'gandalf@me.com', 
              'password1': 'SauronSucks', 
              'password2': 'SauronSucks', 
              'birthdate': datetime(1956, 1, 1),
              'tos': True})
  </code></pre>
  
  <p>I can output the <code>response.content</code> afterwards and the error in the form is 'Please enter a valid date.' I have not overridden the <code>clean</code> method for <code>birthdate</code> in the form. Here's the declaration of the date field from the form:</p>
  
  <pre><code>birthdate = forms.DateField(
          widget=SelectDateWidget(
              years=range(this_year-90, this_year-12)[::-1]),
              required=True,)
  </code></pre>
  
  <p>How the heck do I send it a valid date?</p>