Add ServiceWhiteList model with corresponding tests

tests/app/test_model.py

@@ -1,7 +1,9 @@
 from datetime import datetime
 
+import pytest
+
 from app import DATETIME_FORMAT
-from app.models import Notification
+from app.models import Notification, ServiceWhitelist
 
 
 def test_should_build_notification_from_minimal_set_of_api_derived_params(notify_api):
@@ -70,3 +72,33 @@ def test_should_build_notification_from_full_set_of_api_derived_params(notify_ap
     assert notification.notification_type == 'SMS'
     assert notification.api_key_id == 'api_key_id'
     assert notification.key_type == 'key_type'
+
+
+@pytest.mark.parametrize('mobile_number', [
+    '07700 900678',
+    '+44 7700 900678'
+])
+def test_should_build_service_whitelist_from_mobile_number(mobile_number):
+    service_whitelist = ServiceWhitelist.from_string('service_id', mobile_number)
+
+    assert service_whitelist.mobile_number == mobile_number
+    assert service_whitelist.email_address is None
+
+@pytest.mark.parametrize('email_address', [
+    'test@example.com'
+])
+def test_should_build_service_whitelist_from_email_address(email_address):
+    service_whitelist = ServiceWhitelist.from_string('service_id', email_address)
+
+    assert service_whitelist.email_address == email_address
+    assert service_whitelist.mobile_number is None
+
+
+@pytest.mark.parametrize('contact', [
+    '',
+    '07700dsadsad',
+    'gmail.com'
+])
+def test_should_not_build_service_whitelist_from_invalid_contact(contact):
+    with pytest.raises(ValueError):
+        ServiceWhitelist.from_string('service_id', contact)