fix(juju_kubernetes_cloud): get plan from req.Plan instead of req.State

[SimoneDutto]

Description

Before we were getting the plan from the req.State, so changes were not propagated in the state.
We now set the plan from req.Plan and set it accordingly in the state.

Fixes:

Type of change

• fix When applying changes to juju_kubernetes_cloud, provider provider["registry.terraform.io/juju/juju"] produced an unexpected new value: .kubernetes_config: inconsistent values for sensitive attribute. #664

QA steps

Manual QA steps should be done to test this PR.

Create a k8s_config.txt in the project root by doing microk8s config > k8_config.txt

provider juju {}
resource "juju_kubernetes_cloud" "cluster_k8s_cloud" {
  name              = "k8s-stg-is-iam"
  kubernetes_config = file("k8_config.txt")
}

terraform apply
Change something in the config manually: like adding a comment.
terraform apply again.

Now the apply doesn't error out.

Additional notes

Fly by: cleanup of tests. We were getting the MICROK8S config from an environment variable, but this was not propagated to the test's functions correctly in fact there wasn't any {{.Config}} in the terraform plans.

[hmlanigan]

issue: This overwrites the ID and credential computed values already saved to state.

[SimoneDutto]

I could be wrong, but unmodified fields are passed from the State to the Plan.
Here the terraform doc is very similar to what we do, and they don't get the ID from the State but from the Plan.

[hmlanigan]

It works because of how the schema is defined. You'll have to be careful in the future.

[SimoneDutto]

from my understanding computed values can't be set by the user, so in the plan are always copied from the state. Making setting the state as the plan always correct for computed values.