ParallelScope
The ParallelScope enumeration permits specifying the degree to
which a test and its descendants may be run in parallel.
Children = 2
Descendants of the test may be run in parallel with one another
Fixtures = 4
Descendants of the test down to the level of TestFixtures may be run in parallel
None = 0
No Parallelism is permitted
Self = 1
The test itself may be run in parallel with others at the same level