Those who like you use Metatrader trading platform you have tested dozens sure, maybe hundreds, of making the respective Expert Advisors backtesting the strategy tester. To perform a backtesting over a long period of time will inevitably need the quoted price of the currency pair and for the entire period during which we will test.
In Metatrader 4 is the problem that the number of candles on a chart is limited and therefore limits the price history with which we have to do the backtesting. Metatrader 4 The solution was to manually download the historical prices of candles M1 and then load this data in the Metatrader, although you can download the chart data is better than M1 M1 download and use the script to get a journalist-turned level of acceptable quality modeling for the backtesting is as reliable as possible. Thus we have the problem of gaining access to the information necessary to make our backtesting with good quality directly from the platform, a problem that must be added that not all brokers offer to download files with the historical contributions. Some will be thinking that the History Center of Metatrader 4 is the download function and that what I say is meaningless, so I recommend you read this article about how to make a backtesting in Metatrader 4 before proceeding.
Metatrader 5 on access to historical data M1 is much quicker and easier, indeed in Metatrader 5 only works with graphics data M1, to be handed to the superior temporal, but always using data from 1 minute candles. For example a sail of a 5-minute chart Metatrader 5 is built with data from the five 1-minute candles that compose it. This fact, together with that in Metatrader 5 can establish an unlimited number of candles on a chart (not Metatrader 4) by simply choosing makes monthly charts and back on the chart until the start of it is downloading all historical M1 automatically and that to build this chart are going to download only data M1. And it extends to improving the modeling of backtesting is of the highest quality without the need for additional operations before backtesting.
The History Center of Metatrader 5 or even allows you to view or modify the data as in Metatrader 4, but according MetaQuotes this functionality will be added to the final version of Metatrader 5.