python - How do I test Django QuerySets are equal?

Question

I am trying to test my Django views. This view passes a QuerySet to the template:

def merchant_home(request, slug):
  merchant = Merchant.objects.get(slug=slug)
  product_list = merchant.products.all()
  return render_to_response('merchant_home.html',
                            {'merchant': merchant,
                            'product_list': product_list},
                            context_instance=RequestContext(request))

and test:

  def test(self):
    "Merchant home view should send merchant and merchant products to the template"
    merchant = Merchant.objects.create(name='test merchant')
    product = Product.objects.create(name='test product', price=100.00)
    merchant.products.add(product)

    test_client = Client()
    response = test_client.get('/' + merchant.slug)
    # self.assertListEqual(response.context['product_list'], merchant.products.all())
    self.assertQuerysetEqual(response.context['product_list'], merchant.products.all())

EDIT I am using self.assertQuerysetEqual instead of self.assertListEqual. Unfortunately this still doesn't work, and the terminal displays this: ['<Product: Product object>'] != [<Product: Product object>]

---

assertListEqual raises: 'QuerySet' object has no attribute 'difference' and assertEqual does not work either, although self.assertSetEqual(response.context['product_list'][0], merchant.products.all()[0]) does pass.

I assume this is because the QuerySets are different objects even though they contain the same model instances.

How do I test that two QuerySets contain the same data? I am even testing this correctly? This is my 4th day learning Django so I would like to know best practices, if possible. Thanks.

Answer 1

By default assertQuerysetEqual uses repr() on the first argument. This is why you were having issues with the strings in the queryset comparison.

To work around this you can override the transform argument with a lambda function that doesn't use repr():

self.assertQuerysetEqual(queryset_1, queryset_2, transform=lambda x: x)