Create test_filter.py

[zoharasulin]

HI .
This PR was sent as part of course OSDC taught by: @szabgab.
I add file test to your code filter.py.
I think this tests can help your project when in further- you change the code or maybe add more features.
I see your project and project API that base on your code and it very intersting.
I wonder that was in your list json universities and colleges from Israel(my country :))
Nice job!

[szabgab]

I like these tests very much!

[yigitguler]

Hello! Thank you very much for this contribution.
However, I suspect it is opened to the wrong repository.
This is the repository of the JSON file. The API is located here: https://github.com/Hipo/university-domains-list-api/
Also the build fails to work. I assume this is related with the repository difference.

[zoharasulin]

Hello @yigitguler
First of all I'm sorry it fell.
I did tests and saw that everything was running.
Probably something small in the import.
Regarding what you say, it has nothing to do with your script, I simply saw a filter.py in repo, according to what I understand, sorts the universities and etc.
This is not true?