Redundancy in unsuccessful drag start tests

[ty0002]

See this line... We initialise the dragDataSource mock after we setup the coordinator. When we make the call to the coordinator's creation method we end up passing a nil data source, so during all the tests in this suite the coordinator's data source is nil making most of these tests redundant at present because they won't actually fail.

[ty0002]

I'd like to review these tests to see if we can't make them a bit leaner.