MDL-47497 behat: steps for basic download testing.
MDL-47497 behat: steps for basic download testing.

These steps were created by sam marshall and Jes Ackland-Snow at the Open
University. I just altered them to make them a bit more generic, and
submitted them to Moodle core, at the point when I wanted to reuse them
in another plugin.

This commit introduces two new steps:

Then following "XXX" should download "YY" bytes
Then following "XXX" should download between "YY" and "ZZ" bytes

At the moment, this only works for links with href attributes.

dilawar/moodle