ExpectedSystemExit doesn't work in multi-threading environment

[akryvtsun]

In integration testing if a test is executed on the one thread but System.exit(...) is called on another ExpectedSystemExit work unstable. If the test is finished faster then another thread calls System.exit(...) then current ExpectedSystemExit implementation fails the test.

The solution is to delay the test thread till System.exit(...) is called or time out time is finished. It's possible to use java.util.concurrent.CountDownLatch for this but I couldn't find ability to do the latch count down somewhere in NoExitSecurityManager.

P.S. if ExpectedSystemExit work as a Rule in multi-threading environment isn't break any JUnit conventions I can prepare pull request for the fix.

[akryvtsun]

@stefanbirkner FYI: I've implemented needed functionality in my code using your ProvideSecurityManager and my custom thread-friendly analog of your internal NoExitSecurityManager class.

[stefanbirkner]

Could you provide a pull request that fixes the issue? That would be very helpful.

[akryvtsun]

@stefanbirkner thank you for interest. I'll provide PR.

[akryvtsun]

@stefanbirkner pls, review provided PR with the fix
#46
All tests are green but some firebug check was failed and I can't clearly understand what exactly.

[stefanbirkner]

Thanks for the pull request. I cannot review it the next two weeks, but I review it afterwards.

[akryvtsun]

@stefanbirkner NP. let me know if you will have some notes, remarks etc.