Better error handling for Auditable class

tests/domain/test_invitations.py

@@ -47,7 +47,7 @@ def test_accept_expired_invitation():
     increment = Invitations.EXPIRATION_LIMIT_MINUTES + 1
     expiration_time = datetime.datetime.now() - datetime.timedelta(minutes=increment)
     invite = InvitationFactory.create(
-        user_id=user.id, expiration_time=expiration_time, status=Status.PENDING
+        user=user, expiration_time=expiration_time, status=Status.PENDING
     )
     with pytest.raises(ExpiredError):
         Invitations.accept(user, invite.token)
@@ -57,14 +57,14 @@ def test_accept_expired_invitation():
 
 def test_accept_rejected_invite():
     user = UserFactory.create()
-    invite = InvitationFactory.create(user_id=user.id, status=Status.REJECTED_EXPIRED)
+    invite = InvitationFactory.create(user=user, status=Status.REJECTED_EXPIRED)
     with pytest.raises(InvitationError):
         Invitations.accept(user, invite.token)
 
 
 def test_accept_revoked_invite():
     user = UserFactory.create()
-    invite = InvitationFactory.create(user_id=user.id, status=Status.REVOKED)
+    invite = InvitationFactory.create(user=user, status=Status.REVOKED)
     with pytest.raises(InvitationError):
         Invitations.accept(user, invite.token)
 
@@ -72,7 +72,7 @@ def test_accept_revoked_invite():
 def test_wrong_user_accepts_invitation():
     user = UserFactory.create()
     wrong_user = UserFactory.create()
-    invite = InvitationFactory.create(user_id=user.id)
+    invite = InvitationFactory.create(user=user)
     with pytest.raises(WrongUserError):
         Invitations.accept(wrong_user, invite.token)
 
@@ -80,7 +80,7 @@ def test_wrong_user_accepts_invitation():
 def test_user_cannot_accept_invitation_accepted_by_wrong_user():
     user = UserFactory.create()
     wrong_user = UserFactory.create()
-    invite = InvitationFactory.create(user_id=user.id)
+    invite = InvitationFactory.create(user=user)
     with pytest.raises(WrongUserError):
         Invitations.accept(wrong_user, invite.token)
     with pytest.raises(InvitationError):