Bail if the atomic update fails

This should only happen due to race conditions or inconsistent data.

django_afip/models.py

@@ -1377,12 +1377,16 @@ def approximate_date(receipt: models.Receipt) -> bool:
             return False
 
         # Commit this atomically to avoid race conditions.
-        Receipt.objects.filter(
+        count = Receipt.objects.filter(
             pk=receipt.id,
             receipt_number__isnull=True,
         ).update(
             issued_date=oldest_possible,
         )
+        if count != 1:
+            raise exceptions.DjangoAfipException(
+                f"Expected to update one receipt, updated {count}."
+            )
 
         # Mutate the input object to avoid inconsistency issues.
         receipt.issued_date = oldest_possible

tests/test_models.py

@@ -559,3 +559,17 @@ def test_approximate_date_two_days_ago_without_most_recent() -> None:
 
     assert changed is False
     assert receipt.issued_date == two_days_ago
+
+
+@pytest.mark.django_db()
+@freeze_time("2023-11-16 18:39:40")
+def test_approximate_date_failure() -> None:
+    one_month_ago = date(2023, 10, 16)
+
+    receipt = factories.ReceiptWithApprovedValidation(issued_date=one_month_ago)
+
+    with pytest.raises(
+        exceptions.DjangoAfipException,
+        match="Expected to update one receipt, updated 0.",
+    ):
+        receipt.approximate_date()