Testing get_context_data() on ListView throws 'AttributeError: object has no attribute 'object_list'

I am trying to test my custom get_context_data() method on a ListView and I keep running into this error: AttributeError: 'Home' object has no attribute 'object_list'

The view works fine. Testing that the view responds with 200 status code works fine. I just cannot seem to be able test my custom get_context_data method.

Test

import pytest
from mixer.backend.django import mixer
from django.test import RequestFactory
from django.urls import reverse
from tracker.views import *
from tracker.models import Peak

pytestmark = pytest.mark.django_db


@pytest.fixture
def factory():
    return RequestFactory()

def test_number_of_peaks_completed(factory):
    mixer.cycle(7).blend(Peak, complete=True)
    mixer.cycle(10).blend(Peak)

    path = reverse('home')
    request = factory.get(path)
    view = Home()
    view.setup(request)
    context = view.get_context_data()

    assert context['number_of_peaks_completed'] == 7

View

from django.views.generic import ListView
from tracker.models import *

class Home(ListView):
    model = Peak
    template_name = 'tracker/home.html'
    context_object_name = 'peaks'

    def get_context_data(self, *, object_list=None, **kwargs):
        context = super().get_context_data(**kwargs)
        context['number_of_peaks_completed'] = Peak.objects.filter(complete=True).count()
        return context

Error Trace

FAILED       [ 16%]
tracker/tests/test_views.py:24 (test_number_of_peaks_completed)
factory = <django.test.client.RequestFactory object at 0x7efbfb8093a0>

    def test_number_of_peaks_completed(factory):
        mixer.cycle(7).blend(Peak, completed=True)
        mixer.cycle(10).blend(Peak, completed=False)

        path = reverse('home')
        request = factory.get(path)
        view = Home()
        view.setup(request)
>       context = view.get_context_data()

tracker/tests/test_views.py:33: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
tracker/views.py:19: in get_context_data
    context = super().get_context_data(**kwargs)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <tracker.views.Home object at 0x7efbfb630d00>, object_list = None
kwargs = {}

    def get_context_data(self, *, object_list=None, **kwargs):
        """Get the context for this view."""
>       queryset = object_list if object_list is not None else self.object_list
E       AttributeError: 'Home' object has no attribute 'object_list'

venv/lib/python3.8/site-packages/django/views/generic/list.py:115: AttributeError

The problem is you are not using the standard as_view() function.

If you want to do this manually, you need to set self.object_list yourself (this happens inside the main view function, e.g get).

Try this:

def test_number_of_peaks_completed(factory):
    mixer.cycle(7).blend(Peak, complete=True)
    mixer.cycle(10).blend(Peak)

    path = reverse('home')
    request = factory.get(path)
    view = Home()
    view.setup(request)
    view.object_list = view.get_queryset()
    context = view.get_context_data()

    assert context['number_of_peaks_completed'] == 7

You can move this line to your own get_context_data as well.

Ref: https://github.com/django/django/blob/master/django/views/generic/list.py#L142