The key advantage is that exceptions propagate properly.
If a thread throws an exception (as a result of a failed test assertion, or otherwise) then the test host crashes and must be restarted.

…parameter.

…tion behaviour testing.

This should also allow the test to run on both netcore and netfx.

* Removed two unnecessary iterations from DatabaseHelper.
* Added explanatory comments to ApiShould.
* Switched to using Task.WaitAll rather than waiting for each Task in sequence.

Cancellation can trigger one of several different errors, resulting in a flakier test.
Also ensure that the query always takes more than 150ms, ensuring that a quick query execution doesn't cause the test to fail.
Finally, make sure that we try to read everything from the SqlDataReader.