Terraform Testing on GCP

Build a complete Terraform testing workflow for Google Cloud Storage modules using the built-in `terraform test` command.

You will start by writing `.tftest.hcl` files for a prebuilt GCS bucket module, then run those tests in plan mode for fast feedback, add expected-failure coverage for variable validation, use provider mocking to avoid real API calls, and finish with integration tests that create and verify a real bucket in GCP.

By the end of the lab, you will understand how to combine fast unit-style checks with slower end-to-end tests so your Terraform modules can be validated confidently in local development and CI pipelines.