Terraform Test

# CI/CD Integration

## GitHub Actions

```yaml
name: Terraform Tests

on:
  pull_request:
    branches: [ main ]
  push:
    branches: [ main ]

jobs:
  unit-tests:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: hashicorp/setup-terraform@v3
        with:
          terraform_version: 1.9.0

      - run: terraform fmt -check -recursive
      - run: terraform init
      - run: terraform validate
      - name: Run unit tests (plan mode, no credentials needed)
        run: terraform test -filter=unit_test -verbose

  integration-tests:
    runs-on: ubuntu-latest
    needs: unit-tests
    if: github.ref == 'refs/heads/main'
    steps:
      - uses: actions/checkout@v4
      - uses: hashicorp/setup-terraform@v3
        with:
          terraform_version: 1.9.0

      - run: terraform init
      - name: Run integration tests
        run: terraform test -filter=integration_test -verbose
        env:
          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
```

## GitLab CI

```yaml
stages:
  - validate
  - test

terraform-unit-tests:
  image: hashicorp/terraform:1.9
  stage: validate
  before_script:
    - terraform init
  script:
    - terraform fmt -check -recursive
    - terraform validate
    - terraform test -filter=unit_test -verbose

terraform-integration-tests:
  image: hashicorp/terraform:1.9
  stage: test
  before_script:
    - terraform init
  script:
    - terraform test -filter=integration_test -verbose
  only:
    - main
```

## Recommended CI Strategy

- Run unit tests (plan mode + mock tests) on every PR — fast, no credentials needed
- Run integration tests only on merge to main or nightly — requires cloud credentials
- Use `-filter=unit_test` / `-filter=integration_test` to separate test types based on naming convention
- Store cloud credentials as CI secrets, never in code


# Example Test Suite

Complete example testing a VPC module with unit, integration, and mock tests.

## Unit Tests (Plan Mode)

```hcl
# tests/vpc_module_unit_test.tftest.hcl

variables {
  environment = "test"
  aws_region  = "us-west-2"
}

run "test_defaults" {
  command = plan

  variables {
    vpc_cidr = "10.0.0.0/16"
    vpc_name = "test-vpc"
  }

  assert {
    condition     = aws_vpc.main.cidr_block == "10.0.0.0/16"
    error_message = "VPC CIDR should match input"
  }

  assert {
    condition     = aws_vpc.main.enable_dns_hostnames == true
    error_message = "DNS hostnames should be enabled by default"
  }

  assert {
    condition     = aws_vpc.main.tags["Name"] == "test-vpc"
    error_message = "VPC name tag should match input"
  }
}

run "test_subnets" {
  command = plan

  variables {
    vpc_cidr        = "10.0.0.0/16"
    vpc_name        = "test-vpc"
    public_subnets  = ["10.0.1.0/24", "10.0.2.0/24"]
    private_subnets = ["10.0.10.0/24", "10.0.11.0/24"]
  }

  assert {
    condition     = length(aws_subnet.public) == 2
    error_message = "Should create 2 public subnets"
  }

  assert {
    condition     = length(aws_subnet.private) == 2
    error_message = "Should create 2 private subnets"
  }

  assert {
    condition = alltrue([
      for subnet in aws_subnet.private :
      subnet.map_public_ip_on_launch == false
    ])
    error_message = "Private subnets should not assign public IPs"
  }
}

run "test_outputs" {
  command = plan

  variables {
    vpc_cidr = "10.0.0.0/16"
    vpc_name = "test-vpc"
  }

  assert {
    condition     = output.vpc_id != ""
    error_message = "VPC ID output should not be empty"
  }

  assert {
    condition     = can(regex("^vpc-", output.vpc_id))
    error_message = "VPC ID should have correct format"
  }

  assert {
    condition     = output.vpc_cidr == "10.0.0.0/16"
    error_message = "VPC CIDR output should match input"
  }
}

run "test_invalid_cidr" {
  command = plan

  variables {
    vpc_cidr = "invalid"
    vpc_name = "test-vpc"
  }

  expect_failures = [
    var.vpc_cid