terraform-test

Comprehensive guide for writing and running Terraform tests with assertions, mocking, and module validation. Terraform's built-in testing framework validates that configuration updates don't introduce breaking changes. Tests run against temporary resources, protecting existing infrastructure and state files. Read the relevant reference file when the user asks about mocking, CI/CD integration, or wants a full example. Use *_unit_test.tftest.hcl for plan-mode tests and *_integration_test.tftest.hcl for apply-mode tests so they can be filtered separately in CI. Resources are destroyed in reverse run block order after test completion. This matters for dependencies (e.g., S3 objects before bucket). Use terraform test -no-cleanup to skip cleanup for debugging.