Add Unit test-case for env/env_exporter.py

[ibreakthecloud]

FEATURE REQUEST

Anything else we need to know?:

References :
https://stackoverflow.com/questions/652292/what-is-unit-testing-and-how-do-you-do-it
http://pythontesting.net/framework/unittest/unittest-introduction/

[zaffnet]

I am taking up this issue. Wish me luck.