Testing your Terraform code is crucial to ensure that your infrastructure as code (IaC) is reliable, maintainable, and free of errors. This section will cover various methods and tools for testing Terraform configurations.
Why Test Terraform Code?
Testing Terraform code helps to:
- Catch errors early: Identify syntax errors, misconfigurations, and other issues before they affect your infrastructure.
- Ensure reliability: Verify that your infrastructure behaves as expected.
- Facilitate collaboration: Make it easier for teams to work together by ensuring that changes do not introduce regressions.
- Improve maintainability: Keep your codebase clean and manageable.
Types of Tests
- Syntax and Linting: Ensure that your Terraform code follows best practices and is free of syntax errors.
- Unit Tests: Test individual components of your Terraform code in isolation.
- Integration Tests: Verify that different parts of your infrastructure work together as expected.
- End-to-End Tests: Test the entire infrastructure setup to ensure it meets the desired requirements.
Tools for Testing Terraform Code
- Terraform Validate
terraform validate is a built-in command that checks the syntax and validity of your Terraform configuration files.
- TFLint
TFLint is a linter for Terraform that helps you identify potential issues and enforce best practices.
Installation
Usage
- Terratest
Terratest is a Go library that provides patterns and helpers for writing automated tests for your infrastructure code.
Example Test
package test
import (
"testing"
"github.com/gruntwork-io/terratest/modules/terraform"
)
func TestTerraform(t *testing.T) {
opts := &terraform.Options{
TerraformDir: "../path/to/terraform/code",
}
defer terraform.Destroy(t, opts)
terraform.InitAndApply(t, opts)
// Add assertions here
}
- Kitchen-Terraform
Kitchen-Terraform is a set of Test Kitchen plugins for testing Terraform configurations.
Example Configuration
driver:
name: terraform
provisioner:
name: terraform
verifier:
name: inspec
platforms:
- name: ubuntu
suites:
- name: default
verifier:
inspec_tests:
- path: test/integration/defaultPractical Example
Let's create a simple Terraform configuration and write tests for it.
Terraform Configuration
provider "aws" {
region = "us-west-2"
}
resource "aws_s3_bucket" "example" {
bucket = "my-unique-bucket-name"
acl = "private"
}Terratest Example
package test
import (
"testing"
"github.com/gruntwork-io/terratest/modules/terraform"
"github.com/stretchr/testify/assert"
)
func TestS3Bucket(t *testing.T) {
opts := &terraform.Options{
TerraformDir: "../path/to/terraform/code",
}
defer terraform.Destroy(t, opts)
terraform.InitAndApply(t, opts)
bucketName := terraform.Output(t, opts, "bucket_name")
assert.Equal(t, "my-unique-bucket-name", bucketName)
}Running the Tests
-
Initialize and apply the Terraform configuration:
terraform init terraform apply -
Run the Terratest:
go test -v
Common Mistakes and Tips
- Not validating code: Always run
terraform validatebefore applying changes. - Ignoring linting: Use TFLint to catch potential issues early.
- Skipping tests: Write and run tests regularly to ensure your infrastructure remains reliable.
- Not cleaning up: Ensure that your tests clean up resources to avoid unnecessary costs.
Conclusion
Testing Terraform code is essential for maintaining reliable and error-free infrastructure. By using tools like terraform validate, TFLint, Terratest, and Kitchen-Terraform, you can ensure that your Terraform configurations are robust and meet your requirements. Regular testing helps catch issues early, facilitates collaboration, and improves the maintainability of your codebase.
Terraform Course
Module 1: Introduction to Terraform
Module 2: Terraform Configuration Language
Module 3: State Management
Module 4: Terraform Modules
Module 5: Provisioning Resources
- Provisioning Basics
- Provisioning AWS Resources
- Provisioning Azure Resources
- Provisioning GCP Resources
Module 6: Advanced Terraform Features
Module 7: Terraform Best Practices
Module 8: Terraform in CI/CD
- Integrating Terraform with CI/CD
- Automating Terraform with Jenkins
- Using Terraform with GitHub Actions
- Terraform Cloud and Enterprise