Add support for aborting/bailing out of test cases, which is needed for
implementing assertions.
An assertion is like an expectation, but bails out of the test case
early if the assertion is not met. The idea with assertions is that you
use them to state all the preconditions for your test. Logica
Quoting Brendan Higgins (2019-08-13 22:50:59)
> Add support for aborting/bailing out of test cases, which is needed for
> implementing assertions.
>
> An assertion is like an expectation, but bails out of the test case
> early if the assertion is not met. The idea with assertions is that you
> use
