Refactoring unit-tests related to weekplans_bloc_test

[Fatma-Mondher]

This issue is an extension of issue #565

Weekplans_bloc_test tests functionality related to weekplan_selector_bloc. There are however a number of problems related to the test file. Two of the tests have been commented out and fails when run and therefore needs to be tested. In addition, the choice of tests conducted in the file is not immediately transparent due to lack of or inadequate commenting. It seems that there are functionality in weekplan_selector_bloc that is not tested properly in the file. For this reason the following changes are suggsted:

1. Change of name of tests to conform to normal naming conventions.
2. Fixing of commented out unit tests
3. Implementation of unit tests of those functions that are not tested in the current version of the test-file
4. Suggestions for refactoring functions in weeplan_selector_bloc that serve to extract week numbers from date with non-custom made functions.
5. Suggestions for refactoring functions in weekplan_selector_bloc that do not conform to bloc architecture.