Update validation code for non_emergency contact numbers to accept no…

…n_emergency 3 digit numbers and numbers with extentions

The python port of libphonenumber is much stricter than our old bespoke validation code. As a result it does not accept phone numbers with extensions or phone numbers with 3 digits. This change incorporates the changes to utils that throw an appropriate error, and adds a crude method for handling numbers with extensions. The form will accept any number that returns a TOO_LONG error code, assuming it must be because of an extension (this shouldn't matter as we are not validating whether the phone number is real for notify to send sms notifications to. The service owner will be confident that they're providing the correct number for their service)

app/main/forms.py

@@ -1805,13 +1805,16 @@ def validate(self, *args, **kwargs):
             # and disallow emergency 3-digit numbers
             def valid_non_emergency_phone_number(self, num):
                 try:
-                    number = PhoneNumberUtils(num.data)
-                    normalised_number = number.get_normalised_format()
+                    PhoneNumberUtils(num.data, is_service_contact_number=True)
                 except InvalidPhoneError as e:
-                    raise ValidationError("Enter a phone number in the correct format") from e
-
-                if normalised_number in {"999", "112"}:
-                    raise ValidationError("Phone number cannot be an emergency number")
+                    if e.code == InvalidPhoneError.Codes.UNSUPPORTED_EMERGENCY_NUMBER:
+                        raise ValidationError(str(e)) from e
+                    elif e.code == InvalidPhoneError.Codes.TOO_LONG:
+                        # assume the number is an extension and return the number with minimal normalisation
+                        return True
+
+                    else:
+                        raise ValidationError("Enter a phone number in the correct format") from e
 
                 return True
 

tests/app/main/forms/test_service_contact_details_form.py

@@ -95,3 +95,43 @@ def test_form_phone_number_validation_fails_with_invalid_phone_number_field(noti
         assert not form.validate_on_submit()
         assert len(form.errors) == 1
         assert "Enter a phone number in the correct format" in form.errors["phone_number"]
+
+
+@pytest.mark.parametrize(
+    "short_number, allowed",
+    (
+        ("119", True),
+        ("999", False),
+        ("112", False),
+        (" 999 ", False),
+        ("(9)99", False),
+        ("9-9-9", False),
+    ),
+)
+def test_form_phone_number_allows_non_emergency_3_digit_numbers(notify_admin, short_number, allowed):
+    data = {"contact_details_type": "phone_number", "phone_number": short_number}
+
+    with notify_admin.test_request_context(method="POST", data=data):
+        form = ServiceContactDetailsForm()
+        if allowed:
+            assert form.validate_on_submit()
+            assert len(form.errors) == 0
+            assert form.errors == {}
+        else:
+            assert not form.validate_on_submit()
+            assert len(form.errors) == 1
+            assert form.errors["phone_number"] == ["Phone number cannot be an emergency number"]
+
+
+@pytest.mark.parametrize(
+    "short_number, allowed",
+    (("01572 812241 7081", True),),
+)
+def test_form_phone_number_allows_non_emergency_numbers_with_extensions(notify_admin, short_number, allowed):
+    data = {"contact_details_type": "phone_number", "phone_number": short_number}
+
+    with notify_admin.test_request_context(method="POST", data=data):
+        form = ServiceContactDetailsForm()
+        assert form.validate_on_submit()
+        assert len(form.errors) == 0
+        assert form.errors == {}