I was considering to develop a custom backtesting platform for myself. However, I see that it would require some significant time and effort, and the result might not be as initially expected. So I decided to buy a professional backtesting platform. I live outside of the United States and not interested in US stocks, so my top requirement is being able to enter custom price data as input. It could be as a csv file, data source like Google or Yahoo Finance, or some other way. Also, one should be able to use 3rd party libraries in the strategy code, such that machine learning libraries or ta-lib.
Please suggest some backtesting software for these requirements. It could be both open-source and commercial.