While not mandatory, **tests are recommended** for all modules. A `main.test.ts` file validates that the module works correctly. Tests use **Bun** as the test runner and verify that:

- **Custom configurations** work with different variable values

- **Default configuration** creates expected resources

- **Input validation** catches invalid parameters

- **Required variables** are properly validated

The test framework provides utilities from `~test` import to:

- Initialize Terraform in the module directory

- Apply Terraform with test variables

- Validate the resulting infrastructure state

- Test error conditions and edge cases

Tests run in Docker with `--network=host` capabilities and help ensure module quality and reliability.

Every module requires a `README.md` with YAML frontmatter containing metadata like display name, description, icon, maintainer, and tags. The README must include:

- **Purpose and functionality** - What the module does and when to use it

- **Variable documentation** - All input variables with types, defaults, and descriptions

- **Resource listing** - What Coder resources the module creates

- **Usage examples** - Basic and advanced configuration examples

- **Requirements** - Any prerequisites or dependencies

The documentation format is validated automatically and must pass validation before modules can be accepted. See the [Registry Contributing Guide](https://github.com/coder/registry/blob/main/CONTRIBUTING.md) for detailed formatting requirements and examples.