Normally the StartDate and EndDate variables work for me as expected.

But now I tried testing SPY strategy with data downloaded from Yahoo. When I set:
The Zorro main window says that it's testing 2009 as it's supposed to but the actual results (and equity graph) are from 2009 to 2016.

When you give no end date, the simulation uses the complete historical file. "2009" is not a date, it's the number of the first or last historical data file to be used. "20090101" would be a date.

http://manual.zorro-project.com/date.htm

Thank you, didn't realize that it's tied to the year number of historical data file.