Update test_export_html to work with the Refactoring

[JoshKowi]

Description

The tests for export_html where written before the refactoring took place and need to be modified to work with the new modularized approach.

[JoshKowi]

@holybiber I somehow cannot add the issue to the Project Pywikitools planning

[JoshKowi]

Created a PR for this.

[holybiber]

Closed by #121