Add test for object sleeper

[TobiasNx]

@fsteeg could you help me with the test? the objectSleeper?

[fsteeg]

You should first fix the compiler and build errors (missing imports, wrong file / class name, missing variables, formatting).

Conceptually, the idea looks good, though you will have to call process at some point to actually run the workflow, and instead of the if-statement, you should use something like assertTrue(timeElapsed >= sleepTime) to verify the result. But to compare them like this, they have to be numbers (instead of Instant), e.g. from System.nanoTime().

As expressed by my approval in #495, I think it would be fine to go without a test here, if you don't want to dig into this.

[TobiasNx]

@fsteeg I tried to improve as much as I can. Not sure how to fix the last errors when compiling.

[fsteeg]

Cool, pretty close! I changed sleepTimer.objectSleeper to objectSleeper.process(null) to make it compile, and changed the time to 100 ms to make the test work (and to fail if the sleeper does not wait). Also added a type parameter to ObjectSleeper (<String>) to fix compiler warnings and did some cleanup.