Add unit tests and email to to_dict

Incorporates PR feedback.

uber/tests/models/test_utils.py

@@ -24,3 +24,24 @@ def test_absolute_url_error(base_url):
 
     with pytest.raises(ValueError) as e_info:
         convert_to_absolute_url('////')
+
+class TestCharge:
+    def test_charge_one_email(self):
+        attendee = Attendee(email='test@example.com')
+        charge = Charge(targets=[attendee])
+        assert charge.email == attendee.email
+
+    def test_charge_group_leader_email(self):
+        attendee = Attendee(email='test@example.com')
+        group = Group(attendees=[attendee])
+        charge = Charge(targets=[group])
+        assert charge.email == attendee.email
+
+    def test_charge_first_email(self):
+        attendee = Attendee(email='test@example.com')
+        charge = Charge(targets=[attendee, Attendee(email='test2@example.com'), Attendee(email='test3@example.com')])
+        assert charge.email == attendee.email
+
+    def test_charge_no_email(self):
+        charge = Charge(targets=[Group()])
+        assert charge.email == ''

uber/utils.py

@@ -216,15 +216,15 @@ def _record_email_sent(email):
 
 
 class Charge:
-    def __init__(self, targets=(), amount=None, description=None):
+    def __init__(self, targets=(), amount=None, description=None, email=''):
         self.targets = [self.to_sessionized(m) for m in listify(targets)]
 
         # performance optimization
         self._models_cached = [self.from_sessionized(d) for d in self.targets]
 
         self.amount = amount or self.total_cost
         self.description = description or self.names
-        self.email = self.models[0].email if self.targets and self.models[0].email else ''
+        self.email = self.models[0].email if self.targets and self.models[0].email else email
 
     @staticmethod
     def to_sessionized(m):
@@ -256,7 +256,8 @@ def to_dict(self):
         return {
             'targets': self.targets,
             'amount': self.amount,
-            'description': self.description
+            'description': self.description,
+            'email': self.email
         }
 
     @property