Backtesting is a kind of a strategy test performed on the past data. It can be either automated or manual. For automated backtesting, a special software should be coded. Automated testing is more precise but requires a fully mechanical trading system to test. Manual testing is slow and can be rather inaccurate, but requires no extra programming and can be done without any special preparation process. Any backtesting results should be taken with a grain of salt as the tested strategy might have been created to fit particular backetsting historical data.
Divergence is a tool that helps the traders to learn the price behavior of the currency. This analysis generates patterns that will help to predict the direction of movement of the currency rates. Divergence, a leading indicator, helps traders to significantly increase their profits. This is because the likelihood of trading in the right direction and at the right time increases if this indicator is used along with others such as Moving Averages, Stochastics, RSI, Support and Resistance levels, etc.

Apart from the entry/exit rules and optional money management guidelines, strategies are often characterized by the list of trading tools required to employ the given strategy. These tools are usually charts, technical or fundamental indicators, some market data or anything else that can be used in trading. When choosing a strategy, you need to understand, which of the required tools you have in possession.