Expert Advisor testing can be done with the Smart Forex Tester 1.0 - both on historical data and on live streaming prices...
The release 1.0 will use a new platform (similar to that used by the Forex Simulator)...
Expert Advisor testing as source code is possible with Smart Forex Tester 1.0, which supports strategies as C++. MQ4 is to a great extent compatible to C++.