terraform-test

To write a Terraform test, you create a `.tftest.hcl` file and define run blocks that execute `apply` or `plan` commands. You then use assert blocks to validate the resulting infrastructure state and outputs against expected values.

Mock providers in Terraform testing simulate provider behavior to enable isolated unit testing. They allow you to validate module logic and configuration without provisioning actual cloud resources or making external API calls.

You can validate Terraform plan output by configuring a run block with the `plan` command in your `.tftest.hcl` file. This allows you to use assertions to check expected resource changes and outputs without deploying infrastructure.

Use built-in Terraform testing when you need native integration with `.tftest.hcl` files, run blocks, and mock providers. It is ideal for validating infrastructure as code configurations and preventing regressions directly within the Terraform workflow.

Terraform test failures during an apply block often stem from failed assertions or unexpected resource state changes. You should troubleshoot by verifying your assert block conditions and checking the applied infrastructure state against your expected outputs.

Yes, you can run multiple test scenarios in a single `.tftest.hcl` file by defining multiple run blocks. Each block can independently execute `apply` or `plan` modes and contain specific assertions for isolated validation.