tested • Your client SDK is (or should be) tested • Acceptance Testing • Starts the provider under test • Real resources in use, possibly cost involved (AWS, …) • System Testing • kitchen-terraform • test full Terraform setups with tools like serverspec
so for third-party providers • Download manually • Put in ~/.terraform.d/plugins • Versioning: terraform-provider-vX.Y.Z • Support discussed in hashicorp/terraform#15252