Catching server error in  start and end query parameters for  mysite/search/?q=&start=1&end=20

@paulproteus  I want to resolve #1332 I have caught the exceptions which will raise Http404
to the unusual query parameters 
if we go to  http://openhatch.org/search/?q=&language=Python
and then the following query parameters http://openhatch.org/search/?q=&start=11&end=20&language=Python
and replace the numbers with characters http://openhatch.org/search/?q=&start=banana&end=20&language=Python
we get the error page.I hav modified it to 404 page as the issue suggested.
I am new as a contributor (apology if any mistakes) but another part of the pull request is writing unittests
I would be very greatful if some one can guide me with writing unittests for  /oh-mainline/mysite/search/test.py...query parameters