When writing tests for Django Rest Framework, how are hyperlinked relations supposed to be created?

I'm trying to create a Foo object with a related Bar object, but I'm not sure how I can most efficiently create that relation.

```
# models.py

import uuid

from django.db import models

class Foo(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4)
    bar = models.ForeignKey('Bar')

class Bar(models.Model):
    BarUUID = models.UUIDField(primary_key=True, default=uuid.uuid4

```

---

```
# serializers.py

from rest_framework import serializers
from myapp.models import Bar, Foo

class FooSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Foo
        fields = ('url', 'id', 'bar')

class BarSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Bar
        fields = ('url', 'BarUUID')

```

---

```
# views.py
class FooViewSet(viewsets.ModelViewSet):
    queryset = Foo.objects.all()
    serializer_class = FooSerializer

class BarViewSet(viewsets.ModelViewSet):
    queryset = Bar.objects.all()
    serializer_class = BarSerializer

```

---

```
# urls.py

from rest_framework import routers

router = routers.DefaultRouter()
router.register(r'foos', views.FooViewSet)
router.register(r'bars', views.BarViewSet)

```

---

```
# tests.py

from rest_framework.reverse import reverse
from rest_framework.test import APITestCase

class FooTests(APITestCase):
    def test_create_foo(self):
        bar = Bar.objects.create()

        url = reverse('foo-list')
        data = {
            'bar': # how do I get the URL?
        }

        response = self.client.post(url, data, format='json')

```