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Terratest is a Golang library that helps you write tests for your Terraform stacks, enabling scalable and repeatable infrastructure testing. It allows you to programmatically run Terraform CLI commands and verify the behavior of your Infrastructure as Code (IaC).
You Should Know:
1. Installing Terratest
Ensure you have Go installed, then install Terratest:
go get github.com/gruntwork-io/terratest/modules/terraform
2. Basic Terratest Example
Here’s a simple test to verify Terraform deployments:
package test
import (
"testing"
"github.com/gruntwork-io/terratest/modules/terraform"
)
func TestTerraformAWSExample(t testing.T) {
terraformOptions := &terraform.Options{
TerraformDir: "../examples/aws",
}
defer terraform.Destroy(t, terraformOptions)
terraform.InitAndApply(t, terraformOptions)
// Add assertions here
}
3. Running Tests
Execute tests using:
go test -v ./test
4. Validating AWS Resources
Use AWS SDK to verify resources:
import (
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/service/ec2"
)
func TestEC2InstanceExists(t testing.T) {
svc := ec2.New(session.New())
result, err := svc.DescribeInstances(&ec2.DescribeInstancesInput{
InstanceIds: []string{aws.String("i-1234567890abcdef0")},
})
if err != nil {
t.Fatal(err)
}
assert.NotEmpty(t, result.Reservations)
}
5. Testing Terraform Outputs
output := terraform.Output(t, terraformOptions, "instance_id") assert.NotEmpty(t, output)
6. Using Terratest with CI/CD
Example GitHub Actions workflow:
name: Terratest on: [bash] jobs: test: runs-on: ubuntu-latest steps: - uses: actions/checkout@v2 - name: Set up Go uses: actions/setup-go@v2 with: go-version: '1.16' - run: go test -v ./test
7. Advanced Testing with Mocks
Use Terratest’s `http-helper` to mock API responses:
import "github.com/gruntwork-io/terratest/modules/http-helper"
func TestAPIMock(t testing.T) {
http_helper.HttpDo(t, "GET", "https://api.example.com", nil, nil, 200, "OK", nil)
}
What Undercode Say
Terratest bridges the gap between IaC and automated testing, ensuring reliability in cloud deployments. Key takeaways:
– Always test Terraform before production deployment.
– Use Go’s strong typing for robust assertions.
– Integrate Terratest in CI/CD pipelines for automated validation.
– Combine AWS CLI (aws ec2 describe-instances) and Terratest for deeper checks.
For further reading, visit: Terratest Documentation
Expected Output:
PASS ok ./test 5.123s
References:
Reported By: Darryl Ruggles – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
