Hi, I want to use the azurerm terraform provider in acceptance testing of my provider to create key vault that is an input for the provider. Unfortunately I am not able to include the azurerm as external provider because it requires the feature {} configuration block and the testing framework will not let me to configure it. Is there a way how one could configure the ExternalProvider in the acc test case ?
Hi @simacektomas 
Thank you for raising this and sorry you ran into trouble here.
This ExternalProviders use case should be supported and this may need to be raised as a bug report on the project so the maintainers can triage the issue. You can find the issue tracker for the terraform-plugin-sdk project here: Issues · hashicorp/terraform-plugin-sdk · GitHub
That being said, there have been recent bug fixes to the testing framework for “duplicate provider configurations” errors from Terraform. You may want to ensure you’re on the latest version (go get github.com/hashicorp/terraform-plugin-sdk/v2@v2.24.1 as of this writing) in case the particular issue you are running into is already resolved.