The run expression.
The maximum duration or running.
Exception message.
The file name that the assert failed in. Should be left as default.
The file line that the assert failed in. Should be left as default.
If expression run greater time, will throw an UnitTestException.
// Will throw an exception like "UnitTestException@example.d(6): Expected run time <1 seconds>, but run <2 seconds> {Thread.sleep(2.seconds)}.shouldRunLess(1.seconds);
Used to assert that expression should be run less duration