[fix] Different types of phone numbers are allowed, but only mobile types should

[ujjwalkirti]

I changed the code to check whether phone_number provided is a Mobile number and raise expception if not. (#484 )
Below is the function code that I have altered.

 def validate_phone_number(self, phone_number):
        org = self.context['view'].organization
        if get_organization_radius_settings(org, 'sms_verification'):
            if phonenumbers.phonenumberutil.number_type(phone_number) != 1:
                raise serializers.ValidationError(_('Landline numbers can\'t be used to send SMS.'))
            if not phone_number:
                raise serializers.ValidationError(_('This field is required.'))
            mobile_prefixes = org.radius_settings.allowed_mobile_prefixes_list
            if not self.is_prefix_allowed(phone_number, mobile_prefixes):
                raise serializers.ValidationError(
                    _('This international mobile prefix is not allowed.')
                )
            if User.objects.filter(phone_number=phone_number).exists():
                raise serializers.ValidationError(
                    _('A user is already registered with this phone number.')
                )
        else:
            # Phone number should not be stored if sms verification is disabled
            phone_number = None
        return phone_number

---

Closes #484

Edited by @pandafy

[ujjwalkirti]

@nemesifier can you please review this PR for the issue #484

[nemesifier]

@ujjwalkirti thanks for contributing! We need a failing unit test which replicates the bug before we can merge a fix. Do you know how to write tests? If you look at https://github.com/openwisp/openwisp-radius/blob/master/openwisp_radius/tests/test_api/test_phone_verification.py you can find plenty of examples.

[nemesifier]

I'd write that only mobile phone numbers are allowed.

[ujjwalkirti]

Okay, I will make the required changes.

[pandafy]

Hey @ujjwalkirti!! Thank for contributing. I will be taking over this PR to complete it.