Capacitor : Default values of attributes not being set as expected

[kavuribhavya]

While writing the unit tests for Capacitor connectivity tests/readers/opendss/Capacitors/test_capacitor_connectivity.dss ,
I have come across a few mismatches in the default values of some of the attributes being set for Capacitor object in ditto. The code used for unit testing these attributes is included.

Capacitor

connection_type

 assert m["cap1"].connection_type is None

Ditto returns Y

resistance, reactance

assert m["cap1"].resistance is None
assert m["cap1"].reactance is None

Ditto returns 0.0 for both resistance and reactance

positions

assert m["line1"].positions is None

The default is None but ditto returns an empty list []

substation_name

assert m["cap1"].substation_name is None 

Ditto returns an empty string '' when the default value is None

[kavuribhavya]

OpenDSS Unittests #215

[kavuribhavya]

Fixed all the issues and merged to Master.