Terraform test framework (1.6+) - Mini Project: Build & Apply

Terraform Test Framework Basics

📖 Scenario: You are working on a Terraform module that creates a simple AWS S3 bucket. To ensure your module works correctly, you want to write a basic test using the Terraform test framework introduced in version 1.6.This test will help you verify that the bucket is created with the expected name.

🎯 Goal: Build a Terraform test file that sets up a test environment, applies your module, and checks that the S3 bucket resource is created with the correct bucket name.

📋 What You'll Learn

Create a Terraform test file named bucket_test.go

Use the Terraform test framework syntax introduced in version 1.6

Define a test function named TestS3Bucket

Configure the test to apply the module and check the bucket name output

💡 Why This Matters

🌍 Real World

Terraform tests help ensure your infrastructure code works as expected before deploying to real cloud environments, reducing errors and downtime.

💼 Career

Knowing how to write Terraform tests is valuable for DevOps engineers and cloud architects to maintain reliable infrastructure as code.

1

Create the initial test function and import packages

Write the first lines of the test file bucket_test.go. Import the testing package and the Terraform testing package github.com/hashicorp/terraform-plugin-testing/helper/resource. Then create a test function named TestS3Bucket that takes t *testing.T as a parameter.

Terraform

// Your code here

Need a hint?

Start by declaring the package and importing the required packages. Then define the test function with the exact name TestS3Bucket.

2

Configure the test case with basic settings

Inside the TestS3Bucket function, add a call to resource.Test with a resource.TestCase struct. Set the ProtoV6ProviderFactories field to an empty map map[string]func() (interface{}, error){} to satisfy the provider requirement. Leave other fields empty for now.

Terraform

package test

import (
	"testing"

	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
)

func TestS3Bucket(t *testing.T) {
	// Add resource.Test call with resource.TestCase here
	// Your code here
}

Need a hint?

Use resource.Test and pass a resource.TestCase struct. Set ProtoV6ProviderFactories to an empty map to avoid provider errors.

3

Add the module configuration and apply step

Inside the resource.TestCase, add a Steps field with a slice containing one resource.TestStep. In that step, set the Config field to a Terraform configuration string that creates an AWS S3 bucket resource named test_bucket with the bucket name my-test-bucket. Use the exact Terraform syntax for the resource block.

Terraform

package test

import (
	"testing"

	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
)

func TestS3Bucket(t *testing.T) {
	resource.Test(t, resource.TestCase{
		ProtoV6ProviderFactories: map[string]func() (interface{}, error){},
		// Add Steps with TestStep and Config here
		// Your code here
	})
}

Need a hint?

Define Steps as a slice with one resource.TestStep. Set the Config field to a Terraform string that creates the S3 bucket with the exact name my-test-bucket.

4

Add a check to verify the bucket name attribute

In the resource.TestStep, add a Check field that uses resource.ComposeTestCheckFunc to verify the S3 bucket resource attribute aws_s3_bucket.test_bucket.bucket equals my-test-bucket. Use resource.TestCheckResourceAttr inside the compose function.

Terraform

package test

import (
	"testing"

	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
)

func TestS3Bucket(t *testing.T) {
	resource.Test(t, resource.TestCase{
		ProtoV6ProviderFactories: map[string]func() (interface{}, error){},
		Steps: []resource.TestStep{
			{
				Config: `resource "aws_s3_bucket" "test_bucket" {
  bucket = "my-test-bucket"
}
`,
				// Add Check to verify bucket attribute
				// Your code here
			},
		},
	})
}

Need a hint?

Use Check with resource.ComposeTestCheckFunc and inside it call resource.TestCheckResourceAttr with the resource name, attribute, and expected value.