After clarification from the Terraform team on the failure appearing on the terraform-plugin-testing@v1.6.0, it seems the unknown state is forbidden. In fact, the plan state fails to be printed if used.
They've kindly suggested to use null as a replacement if the value is indeed unkown, which works.
After clarification from the Terraform team on the failure appearing on the
terraform-plugin-testing@v1.6.0, it seems the unknown state is forbidden. In fact, the plan state fails to be printed if used. They've kindly suggested to use null as a replacement if the value is indeed unkown, which works.More info can be found in https://github.com/hashicorp/terraform-plugin-testing/issues/262.