Terraform test framework (1.6+) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the Terraform test framework introduced in version 1.6+?

It allows you to write automated tests for your Terraform configurations to verify that your infrastructure code works as expected before deployment.

intermediate

Which language is used to write tests in the Terraform test framework?

Tests are written in HCL (HashiCorp Configuration Language) using run and check blocks.

intermediate

What is the role of the 'run' block in Terraform tests?

It defines the configuration for running Terraform commands in tests, including the source directory of Terraform code, variables, and environment settings.

advanced

How does the Terraform test framework help with infrastructure state management during tests?

It automatically initializes, applies, and destroys Terraform configurations in isolated test environments to avoid affecting real infrastructure.

beginner

Name one best practice when writing tests using the Terraform test framework.

Keep tests small and focused, clean up resources after tests, and use variables to make tests reusable and maintainable.

What command does the Terraform test framework typically run to prepare infrastructure during tests?

A terraform validate

B terraform plan

C terraform destroy

D terraform apply

The framework runs 'terraform apply' to create or update infrastructure as part of the test setup.

Which programming language do you use to write Terraform tests with the test framework?

A HCL

B JavaScript

C Python

D Ruby

Terraform tests are written in HCL using run and check blocks.

What is the purpose of a destroy run block in tests?

A To initialize Terraform

B To clean up resources after tests

C To validate configuration syntax

D To plan infrastructure changes

A destroy run block removes resources created during tests to avoid leftover infrastructure.

Which of these is NOT a benefit of using the Terraform test framework?

A Manual deployment of resources

B Automated verification of infrastructure code

C Isolated test environments

D Early detection of configuration errors

The framework automates deployment, so manual deployment is not a benefit.

What does a 'run' block NOT typically include?

A Path to Terraform code

B Terraform variables

C Test case assertions

D Cloud provider credentials

run blocks configure Terraform command execution; assertions are written separately in check blocks.

Explain how the Terraform test framework manages infrastructure lifecycle during tests.

Think about setup, verification, and cleanup steps.

Describe best practices for writing maintainable tests using the Terraform test framework.

Consider test design and resource management.

Practice

1. What is the main purpose of the Terraform test framework introduced in version 1.6+?

easy

A. To monitor cloud resources for performance issues

B. To deploy infrastructure faster without manual approval

C. To write automated tests that check your infrastructure code works as expected

D. To replace Terraform CLI commands with a graphical interface

Solution

1. Step 1: Understand Terraform test framework purpose

   The framework is designed to let you write tests that run your Terraform code and verify resource attributes automatically.

2. Step 2: Compare options with framework purpose

   Only To write automated tests that check your infrastructure code works as expected correctly describes writing automated tests for infrastructure code. Other options describe unrelated features.

3. Final Answer:

   To write automated tests that check your infrastructure code works as expected -> Option C

4. Quick Check:

   Test framework purpose = automated infrastructure tests [OK]

Hint: Focus on testing infrastructure code correctness [OK]

Common Mistakes:

• Confusing testing with deployment speed
• Thinking it replaces CLI commands
• Mixing testing with monitoring

2. Which of the following is the correct syntax to define a Terraform test block in version 1.6+?

easy

A. module "test" { ... }

B. terraform_test "example" { ... }

C. resource "test" "example" { ... }

D. test "example" { ... }

Solution

1. Step 1: Recall Terraform test block syntax

   Terraform 1.6+ uses the test "name" { ... } block to define tests.

2. Step 2: Eliminate incorrect syntax options

   Options B, C, and D use incorrect block types or resource/module keywords not related to tests.

3. Final Answer:

   test "example" { ... } -> Option D

4. Quick Check:

   Test block syntax = test "name" [OK]

Hint: Look for the exact 'test' block keyword [OK]

Common Mistakes:

• Using resource or module instead of test block
• Adding extra prefixes like terraform_test
• Confusing test block with resource block

3. Given this Terraform test snippet, what will the test check?

test "check_instance" {
  config = {
    resource "aws_instance" "example" {
      ami           = "ami-123456"
      instance_type = "t2.micro"
    }
  }
  check { 
    resource = "aws_instance.example"
    attribute = "instance_type"
    equals = "t2.micro"
  }
}

medium

A. It checks if the AMI ID is 't2.micro'

B. It checks if the instance type of aws_instance.example is 't2.micro'

C. It verifies the instance is running

D. It validates the resource name is 'aws_instance.example'

Solution

1. Step 1: Analyze the check block

   The check block specifies resource "aws_instance.example", attribute "instance_type", and expects it to equal "t2.micro".

2. Step 2: Match check with options

   It checks if the instance type of aws_instance.example is 't2.micro' correctly states the test checks the instance_type attribute equals "t2.micro". Other options misunderstand attribute or resource checks.

3. Final Answer:

   It checks if the instance type of aws_instance.example is 't2.micro' -> Option B

4. Quick Check:

   Check attribute equals instance_type = t2.micro [OK]

Hint: Focus on attribute and equals fields in check block [OK]

Common Mistakes:

• Confusing AMI ID with instance type
• Assuming runtime status is checked
• Misreading resource name as attribute

4. This Terraform test code fails to run. What is the most likely error?

test "fail_test" {
  config = {
    resource "aws_s3_bucket" "bucket" {
      bucket = "my-bucket"
    }
  }
  check {
    resource = "aws_s3_bucket.bucket"
    attribute = "name"
    equals = "my-bucket"
  }
}

medium

A. The attribute 'name' does not exist for aws_s3_bucket resource

B. The resource block is missing required 'region' argument

C. The test block name cannot contain underscores

D. The equals value must be a number, not a string

Solution

1. Step 1: Check attribute correctness

   The aws_s3_bucket resource uses 'bucket' as the attribute for bucket name, not 'name'. Using 'name' causes the test to fail.

2. Step 2: Verify other options

   Region is usually set in provider, not required here. Test names can have underscores. Equals can be string. So only attribute error is valid.

3. Final Answer:

   The attribute 'name' does not exist for aws_s3_bucket resource -> Option A

4. Quick Check:

   Attribute must match resource schema [OK]

Hint: Check attribute names match resource documentation [OK]

Common Mistakes:

• Using wrong attribute names
• Assuming region is required in resource block
• Thinking test names have naming restrictions
• Confusing data types in equals

5. You want to write a Terraform test that verifies multiple attributes of an AWS EC2 instance, including instance_type and tags. Which approach correctly uses the Terraform test framework to check both attributes in one test?

hard

A. Use multiple check blocks inside one test block, each checking one attribute

B. Create separate test blocks for each attribute check

C. Combine attributes in one check block using a list for attribute and equals

D. Use a single check block with a map for attribute and equals

Solution

1. Step 1: Understand multiple attribute checks in Terraform tests

   The Terraform test framework allows multiple check blocks inside one test block to verify different attributes separately.

2. Step 2: Evaluate options for correctness

   Using multiple check blocks inside one test block, each checking one attribute, correctly verifies different attributes separately. Combining attributes into a single check block using a list or map is not supported. Creating separate test blocks for each attribute check works but is less efficient.

3. Final Answer:

   Use multiple check blocks inside one test block, each checking one attribute -> Option A

4. Quick Check:

   Multiple checks = multiple check blocks [OK]

Hint: Use one check block per attribute inside test [OK]

Common Mistakes:

• Trying to check multiple attributes in one check block
• Splitting checks into many test blocks unnecessarily
• Using unsupported data structures in check block