Entity creation fails if the _profile is an empty list

[itomaldonado]

As per our (AM, MM and MT) conversation on 9/12, an entity could have an empty profile, in other words a list with no events (not a None type but a list()).

But as per testing, this actually fails with an assertion error. See below:

___________________________________________________________________________ TestEntity.test_empty_profile ___________________________________________________________________________

self = <tests.test_entity.TestEntity object at 0x106eb7490>
pilot_entity = {'details': {'cfg': {'agent_launch_method': 'FORK', 'bridges': {'agent_executing_queue': {'bulk_size': 0, 'log_level':...893951416, 'state', 'pmgr.0000', 'MainThread', 'pilot.0000', 'PMGR_LAUNCHING_PENDING', ...), ...], 'uid': 'pilot.0000'}

    def test_empty_profile(self, pilot_entity):
        e = Entity(_uid=pilot_entity['uid'],
                   _etype=pilot_entity['etype'],
                   _profile=[],
>                  _details=pilot_entity['details']
                   )

tests/test_entity.py:158: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <[AttributeError("'Entity' object has no attribute '_etype'") raised in repr()] SafeRepr object at 0x106e97170>, _uid = 'pilot.0000', _etype = 'pilot', _profile = []
_details = {'cfg': {'agent_launch_method': 'FORK', 'bridges': {'agent_executing_queue': {'bulk_size': 0, 'log_level': 'debug', 's...scription': {'access_schema': None, 'candidate_hosts': None, 'cleanup': None, 'cores': 32, ...}, 'etype': 'pilot', ...}

    def __init__(self, _uid, _etype, _profile, _details):
        """
            This is a private constructor for an RA Entity: it gets a series of
            events and sorts it into its properties.  We have 4 properties:
    
              - etype : the type of the entity in question.  This defines, amongst
                        others, what state model the Session will assume to be valid
                        for this entity
              - uid   : an ID assumed to be unique in the scope of an RA Session
              - states: a set of timed state transitions which are assumed to adhere
                        to a well defined state model
              - events: a time series of named, but otherwise unspecified events
            """
    
        assert(_uid)
>       assert(_profile)
E       AssertionError

venv/lib/python2.7/site-packages/radical/analytics/entity.py:27: AssertionError