Two new unit tests

Added unit test for Rule::translateToUrlEncodedPath
Unit tests for all methods of Transformation except getSourceAsPath
You can move this to the getParameter method and rename it to givenASeriesOfParameters or something similar.
As a rule of thumb I only add mocks in the `setUp`method and as property of the test if it is a required dependency (thus: needed in the constructor).

This will make it clear to readers of the unit test what required properties are and will have a positive (albeit small) impact on the performance of your tests.