Django REST API fails tests when saving models, but runs fine

I'm pretty lost on this. I have a ModelViewSet from Django's REST Framework that performs some custom functionality on POST requests by overriding the perform_create method. It looks like this:

class UserViewSet(viewsets.ModelViewSet):
    queryset         = User.objects.all()
    serializer_class = UserFlat

    def perform_create(self, serializer):
         serializer.save()

         try:
             profile_country = self.request.data['country']
             profile_phone = self.request.data['phone']

             profile = Profile.objects.get(user_id=serializer.data['id'])
             country = Country.objects.get(country_code=profile_country)

             # both of these return the object just fine
             # print profile
             # print country

             # Take the profile object and set these attributes. It has a ForeignKey relation with the country
             profile.phone  = profile_phone
             profile.origin = country

             # This is where Django's TestCase fails
             profile.save()

         except:
             print "Attributes not provided"

So I tested the above in my terminal with httpie and it POSTS just fine. When I go to check the DB, every all the information is there. The User object was created and a new Profile object was created with the ForeignKey to the Country and phone number (I create the Profile object with a post_save signal)

When I run the tests though, it fails at the profile.save() section. I've confirmed that the Country object was created in the DB prior to the test and if I print it out while running the test I can see that it clearly picks up the all the relevant info.

http POST :8000/api/v1/users/ username=test password=test last_name=test first_name=test email=test@test.com country=US phone=555

The line above runs in my terminal posts successfully to my database

Here's the failing TestCase though

class APITestCase(TransactionTestCase):
    def test_create_user_profile_through_api(self):
    url = '/api/v1/users/'

    # country = Country.objects.get(country_code='US')

    data = {
        'first_name':'Tom',
        'last_name':'Sawyer',
        'username':'tomsawyer',
        'password':'tomsawyer',
        'email':'tomsawyer@tomsawyer.com',
        'country': 'US',
        'phone':'5555555555'
    }

    # The test fails to save the additional profile information profile.save() within
    # the view's perform_create method. Why is that?
    post = self.client.post(url, data, format='json')

    # request = self.client.get('/api/v1/users/3')
    # Profile.objects.get(id=3) 
    # both lines above are me checking to see if the profile object showed
    # up with the relevant country and phone number fields. Fields are 
    # are empty although the profile object is there

    # I didn't write the assertion yet as the line above keeps coming up empty

When I run my test, the except block of my view comes up "Attributes not provided"

EDIT: On another note, I've checked things like authentication and even turned it off/forced it through the REST Framework and that's all fine. I'm able to successfully post and retrieve from the API and without the API for all other scenarios