Test serializers using factories.

Hello,
During serialization / normalization tests I have encountered a problem, which I am not sure is possible to resolve. Ofc I would like to use factories.
E.g. I test my serializer, using expected payload from server.
```javascript
this.store.normalize('model', payload);
```
Using make / build I can create objects which depend on models - usually fairly distinct from server response payload. Let's suppose I have old system without rest, json-api conventions.
My member factory method (build) returns:
```javascript
{
id: 1,
name: 'member1',
group: 1
}
```
But serializer needs sth like:
```javascript
{
member: {
id: 1
},
group: {
id: 1
}
}
```
I was wondering about sth like:
```javascript
build('member').payload()
```
and define additional hook in factory e.g.
```javascript
FactoryGuy.define('member', {
default: {
...
},
payload(member) {
return {
member: member,
group: member.group
}
}
```

WDYT ? Any possible solutions, ideas ?