With Serverspec, you can write RSpec tests for checking your containers, images or servers are built and configured correctly.
Bats is a TAP-compliant testing framework for Bash. It provides a simple way to verify that the UNIX programs you write behave as expected.
Linting tool for CloudFormation templates
ShellCheck is a GPLv3 tool that gives warnings and suggestions for bash/sh shell scripts.
TaskCat is a python framework for validation of Cloudformation templates over multiple regions and avalability zones
TFLint is a Terraform linter focused on possible errors, best practices, and so on.
A linter for YAML files.