Conftest vs Terratest

Conftest is a free utility for testing structured configuration data, designed for use in CI environments. It uses the Open Policy Agent Rego language to express policies, then evaluates deny, violation, and warning rules within namespaces. Configuration can be read from individual files, directories, multiple files, or standard input. Supported inputs include Kubernetes-style YAML, JSON, HCL and HCL2, Dockerfiles, Terraform-related data, JSONnet, TOML, and XML. Results can be output as plaintext, JSON, TAP, table, JUnit, GitHub, Azure DevOps, or SARIF; the GitHub outputter can annotate test results in workflows. The `conftest verify` command runs policy unit tests. Policies can be pulled from HTTPS URLs, Git repositories, and OCI registries, or pushed to compatible OCI registries. Plugins extend the CLI, with downloads available from sources including OCI, Git, HTTP/HTTPS, Mercurial, and cloud storage. Pre-commit hooks support policy workflows, and integrations are documented for CircleCI, GitHub Actions, and Tekton. Conftest is available for Linux, macOS, and Windows.

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.