Testing For Edible Plants.

I will eat berries that are known to me, other flora I will test first before eating. Personally I would not bother testing for edibility unless (a) I was in urgent need of food, or (b) there was a lot of a certain plant around & I needed to find more edible plants to add to my diet.

Testing For Edibility: 

https://www.backpacker.com/skills/universal-edibility-test

http://www.wikihow.com/Test-if-a-Plant-Is-Edible

http://www.instructables.com/id/The-Edible-Plant-Test/

http://www.survival-expert.com/plants.htm