Discuss: use terratest for testing with Kubernetes

[gxthrj]

I proposal use terratest for testing with Kubernetes. It can test the logic of Kubernetes with code(APIs).

But ingress-controller has CRDs, and the terratest do not CRDs testing.

Anybody has some good ideas?

I found an issue to discuss the feature, need time to digest.

[membphis]

Why we choose terratest? Any reason?

[gxthrj]

Ref to kuma, I saw a feat about terratest.

[gxthrj]

Will add terratest in #101