Added unittests to the test file

Added `character.json` to components folder.
Added unittests to `test.py` file:

The reason I used an array inside the file is because:
- Reading json lose the tuples so I can't do assertEqual
- Using `json.dumps()` in both vars is dirty.
- Some people **may** edit the package directly from PyPi and they don't have the json files.

I've added your doctests inside the unittests.

```
Going-Merry:python fmartingr$ pwd
/Users/fmartingr/Developer/simplediff/python
Going-Merry:python fmartingr$ python test.py
.....
----------------------------------------------------------------------
Ran 5 tests in 0.009s

OK
```