added spec_set to MockModel

[szykin]

Just a little addition to MockModel for testing functions that use getattr().
If you define your MockModel like this:

mock_instance = MockModel(spec_set=True, some_field='some_value')

and try to getattr(mock_instance, 'bad_field') in function that you test it will throw an exception, not add this attribute to MockModel instance.

[codecov-io]

Current coverage is 100% (diff: 100%)

Merging #22 into master will not change coverage

@@           master   #22   diff @@
===================================
  Files           5     5          
  Lines         307   307          
  Methods         0     0          
  Messages        0     0          
  Branches        0     0          
===================================
  Hits          307   307          
  Misses          0     0          
  Partials        0     0          

Powered by Codecov. Last update 793aa27...5d13e37

[szykin]

I assume that even with spec_set=True getattr with default value returns default value.
But raises AttributeError if there is no field with such name in mocked instance.

[stphivos]

Good idea thanks!