File Support

Traceback (most recent call last):
  File "/home/travis/build/pulp/pulp_file/pulp_file/tests/unit/test_serializers.py", line 21, in setUp
    size=1024
  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/django/db/models/query.py", line 413, in create
    obj.save(force_insert=True, using=self.db)
  File "/home/travis/build/pulp/pulp/pulpcore/app/models/content.py", line 166, in save
    super().save(*args, **kwargs)
  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/django/db/models/base.py", line 718, in save
    force_update=force_update, update_fields=update_fields)
  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/django/db/models/base.py", line 748, in save_base
    updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/django/db/models/base.py", line 831, in _save_table
    result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/django/db/models/base.py", line 869, in _do_insert
    using=using, raw=raw)
  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/django/db/models/query.py", line 1136, in _insert
    return query.get_compiler(using=using).execute_sql(return_id)
  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/django/db/models/sql/compiler.py", line 1288, in execute_sql
    for sql, params in self.as_sql():
  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/django/db/models/sql/compiler.py", line 1241, in as_sql
    for obj in self.query.objs
  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/django/db/models/sql/compiler.py", line 1241, in <listcomp>
    for obj in self.query.objs
  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/django/db/models/sql/compiler.py", line 1240, in <listcomp>
    [self.prepare_value(field, self.pre_save_val(field, obj)) for field in fields]
  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/django/db/models/sql/compiler.py", line 1192, in pre_save_val
    return field.pre_save(obj, add=True)
  File "/home/travis/build/pulp/pulp/pulpcore/app/models/fields.py", line 54, in pre_save
    file._file = TemporaryDownloadedFile(open(file.name, 'rb'))
FileNotFoundError: [Errno 2] No such file or directory: ''