I have looked at Zipline before, but it does not handle intraday trades, and does some guesses on when the trade executes during the "day", so you may not get the best price.
Running an algorithm for multi-day trades for more than a few months does not make sense on how the markets move, as certain events like "brexit", earnings, M&A, etc... affect stock price.
If you are really interested in algorithmic trading, and you have programming experience, it's best to build your own backtesting system with intraday market data (pay for this).
This way you will know the ins and outs of a trading system.
Running an algorithm for multi-day trades for more than a few months does not make sense on how the markets move, as certain events like "brexit", earnings, M&A, etc... affect stock price.
If you are really interested in algorithmic trading, and you have programming experience, it's best to build your own backtesting system with intraday market data (pay for this).
This way you will know the ins and outs of a trading system.