def test_date_due_not_set_small_invoice(self):
        Subscription.objects.all().delete()
        plan = DefaultProductPlan.objects.get(
            edition=SoftwarePlanEdition.STANDARD,
            product_type=SoftwareProductType.COMMCARE,
            is_trial=False
        ).plan.get_version()

        subscription_length = 5  # months
        subscription_start_date = datetime.date(2016, 2, 23)
        subscription_end_date = add_months_to_date(subscription_start_date, subscription_length)
        subscription = generator.generate_domain_subscription(
            self.account,
            self.domain,
            date_start=subscription_start_date,
            date_end=subscription_end_date,
            plan_version=plan,
        )

        invoice_date_small = utils.months_from_date(subscription.date_start, 1)
        tasks.generate_invoices(invoice_date_small)
        small_invoice = subscription.invoice_set.first()

        self.assertTrue(small_invoice.balance <= SMALL_INVOICE_THRESHOLD)
        self.assertIsNone(small_invoice.date_due)
Date Due doesn't get set if the invoice is small
dataset/ETHPy150Open dimagi/commcare-hq/corehq/apps/accounting/tests/test_invoicing.py/TestInvoice.test_date_due_not_set_small_invoice