Can this plant be eaten safely?

I went on a trek last week going to the mountain close to my city. As I was walking down the path, I notice some plants. I went closer and checked them; However, I was my first time to see them and I felt that maybe the plants are a kind of vegetables. Here are the pictures of the plant. I wanted to try cooking and eating the plant but I have no idea on how to test a plant whether it is edible or not. Maybe some of you knows this plant and that I may add this plant to my diet.