Port conflicts during tests

When I was running tests in very large and sophisticated system I found very interesting problem. During integration tests run in parallel there was port conflicts and port collision prevents tests to run smoothly and in the end they failed. To avoid this behavior I suggested to use very simple solution. My colleagues confirm the need and implementation was done in very short time. Just before you read the solution - please reconsider situation on your own:

• Tests runs on many JVMs
• You don't want to share state between mentioned above JVMs
• You don't want to manually change every test to enter code

The solution suggested was to use random port in range and repeat this until success. Really simple and it just works. 

From technical perspective please focus on this closure from tests:

Server server = new AvailablePortScanner(minPort, maxPort).tryToExecuteWithFreePort(new Closure<Server>(this) {
    @Override    public Server call(Object... args) {
        Integer freePort = (Integer) args[0];
        Server server = new Server(freePort);
        System.setProperty("port", freePort.toString());
        return server;
    }
});

Checkout on branch:

origin/groovy/closure_port_scanner

to play with it. Have fun