[Answer]-Django get all, with related models

Just create serializer for your related model:

class TestRelationSerializer(serializers.ModelSerializer):

    class Meta:
        meta = TestRelation

and use is as field in TestModelSerializer:

class TestModelSerializer(serializers.ModelSerializer):
    related_model = TestRelationSerializer()

You can also do it other way around, by using TestModelSerializer as field in TestRelationSerializer with many set to true:

class TestRelationSerializer(serializers.ModelSerializer):
    testmodel_set = TestModelSerializer(many=True)

just remember, you can’t do both at once due to infinite recursion it makes.