terraform-test

Validate Terraform modules by creating `.tftest.hcl` files with `test`, `run`, and `assert` blocks to execute unit and integration tests. Unit tests use `plan` mode to validate configuration without creating resources; integration tests use `apply` mode to verify actual infrastructure behavior. This catches configuration errors and prevents breaking changes before deployment.

Plan mode executes unit tests that validate configuration logic and outputs without provisioning actual infrastructure, enabling fast feedback loops. Apply mode runs integration tests that create real resources to verify end-to-end behavior. Choose plan mode for rapid unit testing and apply mode for validating infrastructure reliability.

Mock providers simulate provider behavior for isolated, cost-free unit tests when using Terraform 1.7.0 or later. They accelerate feedback loops by allowing configuration validation without provisioning actual infrastructure, reducing testing time and expenses while maintaining test coverage.

Terraform tests support variable scoping within `run` blocks and respect variable precedence rules defined in `.tftest.hcl` files. Manage test inputs by setting variables at the test block level, ensuring each test case receives correct configuration and validating module behavior across different input scenarios.

Module sourcing in Terraform tests has constraints around registry modules and local module paths. Local modules work directly; registry modules may require specific handling. Check module source compatibility and test structure requirements to avoid sourcing errors during test execution.

Configure cleanup and destruction behavior by defining test block lifecycle rules that control resource teardown after each test runs. This ensures tests remain isolated and prevents resource drift, enabling reliable test reruns and maintaining infrastructure consistency across test suites.