cfn-lint vs Terratest

cfn-lint is a free, open-source validator for AWS CloudFormation YAML and JSON templates. It checks templates against resource provider schemas and applies additional rules, including validation of property values and best practices. AWS Serverless Application Model templates are processed after transformation with AWS SAM. Users can configure built-in checks through command-line options, configuration files, or CloudFormation template metadata, and can add custom rules. Results can be emitted as quiet, parseable, JSON, JUnit, pretty, or SARIF output. Installation options documented by the project include pip, Homebrew for macOS, and Docker; supported Python versions are 3.10 through 3.14. Listed integrations include Atom, Emacs, NeoVim/Vim, Sublime, Visual Studio Code, IntelliJ IDEA, GitHub Actions, and pre-commit. The project treats complex template-value validation as best effort and does not fail merely because it cannot interpret or translate a value. The repository identifies its license as MIT No Attribution, and the plan costs nothing.

Terratest is an open-source Go library for writing automated tests for infrastructure code. Its helpers cover Terraform, OpenTofu, Terragrunt, Packer, Helm, Docker, and Kubernetes, as well as AWS, Azure, and GCP APIs. Tests can run infrastructure tools, deploy real resources, validate the resulting environment, and remove resources afterward. Validation can use HTTP requests, API calls, SSH connections, and shell commands. The documentation covers unit, integration, and end-to-end tests, along with parallelism, retries, error handling, and static analysis. Terratest runs locally and supports configuration-compliance checks, provisioning tests, deployed checks, and policy as code. The project is free under the Apache 2.0 License. The quick start requires Go 1.26 or later and OpenTofu or Terraform for its examples. The documentation recommends cleaning up after tests because they may create resources in real environments. General questions and issue reports go through GitHub Discussions and Issues; Gruntwork offers commercial support to companies using Terratest in production. The v1 line receives security fixes only while v2 is in development.