Context error while testing RESTful API URL

Dear community and forum,

I am in charge of developing RESTful API URLs for a website project. However, when it comes to testing I have got that error:

self = HyperlinkedIdentityField('api:request')
value = <ResourceRequest: JoKLLwwKqxrkrwWmcjOWzIscGzpsbgWJqRAOZabnwxQpiEDRfifeZhvzpRRp...ewyOFcaQVhchYNVIhUoiWBzKMrFYvYQBMNRZsLFfOZSjclHUXwyXZQHxjMtbHvWefMIlyZqvTvXqiu>

def to_representation(self, value):
    assert 'request' in self.context, (
        "`%s` requires the request in the serializer"
        " context. Add `context={'request': request}` when instantiating "
>           "the serializer." % self.__class__.__name__
    )
E       AssertionError: `HyperlinkedIdentityField` requires the request in the serializer context. Add `context={'request': request}` when instantiating the serializer.

/usr/lib/python2.7/site-packages/rest_framework/relations.py:351: AssertionError

The serialiser is (sorry for the ugly code so far):

class ResourceRequestSerializer(serializers.ModelSerializer):
    # context = self.kwargs.get('context', None)
    # request = kwargs['context']['request']
    # print(kwargs)
    view_name = 'api:request'
    url = serializers.HyperlinkedIdentityField(view_name)
    # print(self)
    # url = URLField(view_name=view_name, read_only=True, many=True)
    # url = serializers.SerializerMethodField()
    support_level = serializers.SerializerMethodField()
    originator = BriefUCLProfileSerializer(source='originator.ucl_profile')
    sponsor = BriefUCLProfileSerializer()
    versioned_dependencies = serializers.StringRelatedField(many=True)
    types_of_work = serializers.StringRelatedField(many=True)
    previous = serializers.SerializerMethodField()
    status_history = RequestStatusChangeSerializer(many=True)

For the test:

# Change the status through a POST request
response = self.app.post(
    reverse(
        'api:request',
        args=[request1.pk],
    ),
    params={
        'context': request1,
        'format': 'json',
        'status': ResourceRequest.STATUS_APPROVED,
    },
    # context=request1,
    headers=self.auth_headers,
)

I am still wondering if the context has to be passed from within the serialiser or from the test.

Any help greatly appreciated !

Thank you

Roland