Refactor GoogleSafeBrowsingTest
Refactor GoogleSafeBrowsingTest

The refactoring includes such operations as:
* introducing more test methods for better division of tests, not only according
to tested methods but also according to different arguments and responses to a
test
* having all fixtures being prepared in methods, rather than providing some
of them as class properties
* preparing for changes in implementation

piotr-rusin/spam-lists