You can initialize any python-nitrate object using the "inject"
(short for initial object dict). If you adhere to the format which
is sent by the server in xmlrpc calls I guess you should achieve
what you are looking for:

    #!/usr/bin/python
    
    import nitrate
    
    inject = {'alias': None,
        'arguments': 'X=3',
        'attachment': [],
        'author': 'shillman',
        'author_id': 1472,
        'case_id': 1234,
        'case_status': 'CONFIRMED',
        'case_status_id': 2,
        'category': '--default--',
        'category_id': 1,
        'component': [],
        'create_date': '2008-02-25 15:15:55',
        'default_tester': 'user',
        'default_tester_id': 1791,
        'estimated_time': '00:00:30',
        'extra_link': None,
        'is_automated': 0,
        'is_automated_proposed': False,
        'notes': None,
        'plan': [155],
        'priority': 'P1',
        'priority_id': 1,
        'requirement': None,
        'reviewer': None,
        'reviewer_id': None,
        'script': None,
        'summary': 'Thunderbird: Writing new mail',
        'tag': [],
        }
    
    case = nitrate.TestCase(inject)
    print case.arguments

This seems to work just fine:

    $ COLOR=0 CACHE=0 DEBUG=2 python inject.py 
    [DEBUG] Coloring disabled
    [DEBUG] Caching on level 0
    [DEBUG] Initializing test case TC#0001234
    [DEBUG] Initializing CaseTags for TC#0001234 from the inset
    [DEBUG] []
    X=3

Does that resolve your use case?

Hi Petr,

Your example doesn't work for python-nitrate-0.9-0.

$ CACHE=0 DEBUG=2 python r.py 
[DEBUG] Caching on level 0
[DEBUG] Coloring enabled
Traceback (most recent call last):
  File "r.py", line 32, in <module>
    case = nitrate.TestCase(inject)
  File "/usr/lib/python2.7/site-packages/nitrate/api.py", line 3133, in __init__
    Mutable.__init__(self, id, prefix="TC")
  File "/usr/lib/python2.7/site-packages/nitrate/api.py", line 1564, in __init__
    Nitrate.__init__(self, id, prefix)
  File "/usr/lib/python2.7/site-packages/nitrate/api.py", line 479, in __init__
    self._id = int(id)
TypeError: int() argument must be a string or a number, not 'dict'

Please, test with the latest packages from the testing repo:
http://psss.fedorapeople.org/python-nitrate/testing/download/

Consistent use of the inject was implemented as part of the:

> The Big Cleanup of Ininitialization and Caching
> 
> Initialization check now handled in _is_initialized()
> Cache indexing performed in common _index() method
> Better string representation for incomplete objects
> Consistent use of inject (initial object dictionary)
> Fixed sleep/wake functionality for containers caching
> Simplified _fetch() with injects and use of _index()
> Many unit tests adjusted and improved for caching

https://github.com/psss/python-nitrate/commit/0ff3145

Marking as MODIFIED, move back to ASSIGNED if it does not work as
you would expect. Thanks.

Hi, Sorry for the noise before. I've run it now with python-nitrate-0.11-0.el7.

My use case is about creating new test case with as much attributes as possible in the constructor call (so I don't need to set them later in cycle).

The 'arguments' field is still not set. Also the 'requirement'.

Created attachment 872597 [details]
reproducer_2

New reproducer, which tries to set almost all fields accepted by TestCase.create call.

Output of the reproducer follows. 
There is some inconsistency between tcms and python-nitrate field names which IMHO should be kept as it is now (default_tester, estimated_time, extra_link, is_*)
Container-like bug, plan, tag are expected to be different IMHO too.
However fields setup/effect/breakdown/action are missing completely (RFE bug maybe?)

$ python reproducer.py
action ( do something ) --> !! AttributeError !!
arguments ( THIS="is argument ) --> None
breakdown ( in case of emergency break the glass ) --> !! AttributeError !!
bug ( 1,2,3 ) --> !! AttributeError !!
case_status ( CONFIRMED ) --> !! AttributeError !!
category ( Sanity ) --> Sanity
default_tester ( lzachar@redhat.com ) --> !! AttributeError !!
effect ( something will happen ) --> !! AttributeError !!
estimated_time ( 00:00:01 ) --> !! AttributeError !!
extra_link ( http://localhost ) --> !! AttributeError !!
is_automated ( 1 ) --> !! AttributeError !!
is_automated_proposed ( 1 ) --> !! AttributeError !!
plan ( [10769] ) --> !! AttributeError !!
priority ( P2 ) --> P2
product ( RHEL Tests ) --> <class 'nitrate.api.NitrateNone'>
requirement ( requirement1 and 2 ) --> 
script ( /nonexistent/script/path/ ) --> /nonexistent/script/path/
setup ( build a plane ) --> !! AttributeError !!
summary ( some summary text ) --> some summary text
tag ( tag1,tag2 ) --> !! AttributeError !!
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*--*-*-*-*-*-*-*-*-*-*-*-*-*-*
arguments --> None
author --> Lukas Zachar
automated --> True
autoproposed --> False
bugs --> 
category --> Sanity
components --> [None]
created --> 2014-03-10 16:33:37
id --> 304481
identifier --> TC#0304481
link --> 
manual --> False
notes --> 
priority --> P2
product --> <class 'nitrate.api.NitrateNone'>
requirement --> 
script --> /nonexistent/script/path/
status --> PROPOSED
summary --> some summary text
synopsis --> TC#0304481 - some summary text (Sanity, P2, PROPOSED, 0 test plans)
tags --> 
tester --> None
testplans --> [None]
time --> 00:00:00

I see, thanks for clarifying. I've fixed both "arguments" and
"requirement" (by mistake omitted from the _create() method).

    https://github.com/psss/python-nitrate/commit/1c83e07

Regarding the setup/effect/breakdown/action fields: This is for a
separate RFE, low priority for now as it seems these fields are
not very useful for automated processing. Could be in the future.

python-nitrate-1.0-0.fc20 has been submitted as an update for Fedora 20.
https://admin.fedoraproject.org/updates/python-nitrate-1.0-0.fc20

Package python-nitrate-1.0-0.fc20:
* should fix your issue,
* was pushed to the Fedora 20 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing python-nitrate-1.0-0.fc20'
as soon as you are able to.
Please go to the following url:
https://admin.fedoraproject.org/updates/FEDORA-2014-5095/python-nitrate-1.0-0.fc20
then log in and leave karma (feedback).

python-nitrate-1.0-0.fc20 has been pushed to the Fedora 20 stable repository.  If problems still persist, please make note of it in this bug report.