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At least the current Vaadin TestBench version is still based on Selenium Remote Control, so I'm afraid best experiences are still from that ancestor. It probably works "fine", but I'm afraid you'll have to do lots of manual work between actual commands to make sure asynchronous Vaadin activity has stabilized. This is the same issue one have with older Selenium versions. If you have lots of test to build, I'd suggest to invest on TestBench at this time.