Why my testing view response is none?

Question

I have a post detail view as below.

class PostDetailView(AjaxResponseMixin, UpdateView):
model = UserPost
context_object_name = 'post'
template_name = 'feed/post_detail.html'
form_class = CommentForm

def get_initial(self):
    initial_data = super(PostDetailView, self).get_initial()
    obj = self.get_object()
    initial_data.update({
        "content_type": obj.get_content_type,
        "object_id": obj.id
    })
    return initial_data

def get_context_data(self, **kwargs):
    # comment_form = CommentForm
    context = super(PostDetailView, self).get_context_data(**kwargs)
    kwargs['form_comment'] = context['form']  # comment_form
    try:
        total_views = r.incr('userpost:{}:views'.format(self.object.pk))
        kwargs['total_views'] = total_views
    except (redis.exceptions.ConnectionError,
            redis.exceptions.BusyLoadingError):
        pass

    return super(PostDetailView, self).get_context_data(**kwargs)

def get_success_url(self):
    try:
        total_views = r.incr('userpost:{}:views'.format(self.object.pk))
    except (redis.exceptions.ConnectionError,
            redis.exceptions.BusyLoadingError):
        pass
    return reverse_lazy('feed:post_detail', kwargs={'pk': self.object.pk})

def form_valid(self, form):
    c_type = form.cleaned_data.get("content_type")
    obj_id = form.cleaned_data.get('object_id')
    content_data = form.cleaned_data.get("content")
    parent_obj = None
    try:
        parent_id = int(self.request.POST.get("parent_id"))
    except:
        parent_id = None

    if parent_id:
        parent_qs = Comment.objects.filter(pk=parent_id)
        if parent_qs.exists() and parent_qs.count() == 1:
            parent_obj = parent_qs.first()

    new_comment, created = Comment.objects.get_or_create(
        user=self.request.user,
        content_type=c_type,
        object_id=obj_id,
        content=content_data,
        parent=parent_obj,
    )
    if created:
        ct = ContentType.objects.get_for_id(c_type.id)
        obj = ct.get_object_for_this_type(pk=obj_id)
        create_action(self.request.user, 'commented on', obj)
    return super(PostDetailView, self).form_valid(form)

def form_invalid(self, form):
    print("invalid form")

I am writing test case as below.

class PostDetailViewTests(TestCase):
@classmethod
def setUpTestData(cls):
    user = User.objects.create_user(username='chitra', password='password123')
    cls.post = UserPost(author=user, post_body="Test post", )
    cls.post.save()


def setUp(self):
    login = self.client.login(username='chitra', password='password123')
    user = auth.get_user(self.client)
    assert user.is_authenticated

def test_postdetail_view_page_status_code(self):
    """
    Test that a PostDetailView page is rendering correctly
    """
    response = self.client.get(reverse_lazy('feed:post_detail', kwargs={'pk': self.post.pk}))
    self.assertEquals(response.status_code, 200, 'post doesnt exist with pk={}'.format(self.post.pk))
    self.assertTemplateUsed(response, 'feed/post_detail.html', 'Template used is wrong')

def test_postdetail_view_post_comment(self):
    """
    Test that a comment is posted ot post correctly
    """
    user = User.objects.get(pk=1)
    resp = self.client.post(reverse_lazy('feed:post_detail', kwargs={'pk': self.post.pk}), {'content': 'just a comment'})
    self.assertEqual(resp.status_code, 200)
    # co.refresh_from_db()
    self.assertTrue(Comment.objects.filter().exists())

Comment/forms.py

class CommentForm(ModelForm):

class Meta:
    model = Comment
    fields = ['content_type', 'object_id', 'content']  # list of fields you want from model
    widgets = {'content_type':  HiddenInput(), 'object_id': HiddenInput(),
        'content': Textarea(attrs={'rows': 4, 'cols': 65}),
   }

comment/models.py

class Comment(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, default=1)
content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
object_id = models.PositiveIntegerField()
content_object = GenericForeignKey('content_type', 'object_id')
parent = models.ForeignKey("self", null=True, blank=True, on_delete=models.CASCADE)
content = models.TextField()
timestamp = models.DateTimeField(auto_now_add=True)
objects = CommentManager()

Ok, Here, 'test_postdetail_view_page_status_code' test is passing but posting is getting failed i.e 'test_postdetail_view_post_comment', The resp is None here!

Basically, the view is just a display of a post, and a comment form along with comment list(If there are any), The comment body(i.e field content) is the only input parameter, and content types are used to save the comment object as shown. I am using method 'get_initial', to initialise the content type object with post id(please see), I think the resp is None because I need to first call the display as self.client.get and then use self.client.post here?, I think the get_initial is not getting called, so it's not having content type data right? I am not sure how to debug this to check where the test case is failing!

Any light on this is highly appreciated, Thank you!