Create unit tests for MSOutput

[todor-ivanov]

Impact of the new feature
MicroServices

Is your feature request related to a problem? Please describe.
This is a followup from this PR #9772 (review)
We need to create unit tests for MSOutput, but because of MongoDB dependencies this task turnes into a non trivial one. For testing any of the methods inside the MSOutput Class, one needs an instance of it, but then we need the MongoDb to be up and running in the container for the unit tests - which is not the case for the moment. So far the whole thing is breaking with [1]. And even more,. We also need to explore how would this behave when the Unit test is about to be run by Jenkins.

[1]

[dmwm@a4e07b4a650f Unified_t]$ nosetests MSOutput_t.py
/home/dmwm/unittestdeploy/wmagent/1.3.6.pre4/sw/slc7_amd64_gcc630/external/py2-cryptography/2.4.2-comp2/lib/python2.7/site-packages/cryptography/hazmat/bindings/openssl/binding.py:163: CryptographyDeprecationWarning: OpenSSL version 1.0.1 is no longer supported by the OpenSSL project, please upgrade. A future version of cryptography will drop support for it.
  utils.CryptographyDeprecationWarning
E
======================================================================
ERROR: Test the getCampaignConfig method
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/dmwm/wmcore_unittest/WMCore/test/python/WMCore_t/MicroService_t/Unified_t/MSOutput_t.py", line 47, in setUp
    self.ms = MSOutput(self.msConfig, 'MSOutputConsumer')
  File "/home/dmwm/wmcore_unittest/WMCore/src/python/WMCore/MicroService/Unified/MSOutput.py", line 134, in __init__
    self.msOutDB = MongoDB(**msOutDBConfig).msOutDB
  File "/home/dmwm/wmcore_unittest/WMCore/src/python/WMCore/Database/MongoDB.py", line 47, in __init__
    raise ex
ServerSelectionTimeoutError: localhost:8230: [Errno 111] Connection refused
-------------------- >> begin captured logging << --------------------
root: DEBUG: Reading mocked SiteDB data from the file /home/dmwm/wmcore_unittest/WMCore/test/python/../data/Mock/SiteDBMockData.json 
root: INFO: Configuration including default values:
...

root: DEBUG: Initializing CRIC with url: https://cms-cric.cern.ch/
root: ERROR: Could not connect to MongoDB server: mongodb://localhost
localhost:8230: [Errno 111] Connection refusedGiving up Now.
--------------------- >> end captured logging << ---------------------

----------------------------------------------------------------------
Ran 1 test in 30.127s

FAILED (errors=1)

Describe the solution you'd like
Create unit tests for MSOutput.

Describe alternatives you've considered
No alternatives

Additional context