AsserrtTemplateUsed fails despite template being used...?

I have a view:

class DashboardView(TemplateView):
    template_name = "dashboard/dashboard.html"

Which I am testing using TestCase:

class TestAuthorisedViews(TestCase):

    @classmethod
    def setUpTestData(cls):
        cls.url = reverse('dashboard')
        cls.client = Client()
        cls.response = cls.client.get(cls.url)

    def test_view_uses_correct_template(self):
        print('template', self.response.__dict__)
        self.assertTemplateUsed(self.response, 'dashboard/dashboard.html')

This test fails with AssertionError: No templates used to render the response.

However, the print() debug I included in the test reveals the response does use a template:

template {'template_name': ['dashboard/dashboard.html'], 'context_data': {
     'view': <dashboard.views.DashboardView object at 0x0000019E9CF33040> }, // etc >}

Am I using this test correctly? When looking at the source code, it seems the error fails because response.templates = [] rather than response.templates = None.