Blade Weaving Applies on Non-Damaging Ability

It states"Damaging an enemy champion with a spell...". However, just placing Tristana's E on a target will provide a stack (prior to damage). It's probably not the best for her anyway and she's not in a great spot but it is still inconsistent with the description.

I'm also not sure if this mastery only amplifies a champion's raw basic attack or if it takes items into consideration too.