Testing Guide

This repository uses a comprehensive three-layer testing strategy to ensure reliability and correctness at every level of the infrastructure deployment pipeline.

Quick Start
Test Layers Overview
Running Tests
Unit Tests (BATS)
Infrastructure Tests (OpenTofu)
Integration Tests
Test Helpers Reference
Writing New Tests
Extending Test Helpers

Quick Start

# Run all tests
make test-all

# Run specific test types
make test-unit          # BATS unit tests
make test-tofu          # OpenTofu infrastructure tests
make test-integration   # End-to-end integration tests

# Run tests for a specific module
make test-unit MODULE=frontend
make test-tofu MODULE=frontend
make test-integration MODULE=frontend

Test Layers Overview

Our testing strategy follows a pyramid approach with three distinct layers, each serving a specific purpose:

                            ┌─────────────────────┐
                            │  Integration Tests  │   Slow, Few
                            │  End-to-end flows   │
                            └──────────┬──────────┘
                                       │
                       ┌───────────────┴───────────────┐
                       │       OpenTofu Tests          │   Medium
                       │   Infrastructure contracts    │
                       └───────────────┬───────────────┘
                                       │
           ┌───────────────────────────┴───────────────────────────┐
           │                     Unit Tests                        │   Fast, Many
           │              Script logic & behavior                  │
           └───────────────────────────────────────────────────────┘

Layer	Framework	Purpose	Speed	Coverage
Unit	BATS	Test bash scripts, setup logic, error handling	Fast (~seconds)	High
Infrastructure	OpenTofu	Validate Terraform/OpenTofu module contracts	Medium (~seconds)	Medium
Integration	BATS + Docker	End-to-end workflow validation with mocked services	Slow (~minutes)	Low

Running Tests

Prerequisites

Tool	Required For	Installation
`bats`	Unit & Integration tests	`brew install bats-core`
`jq`	JSON processing	`brew install jq`
`tofu`	Infrastructure tests	`brew install opentofu`
`docker`	Integration tests	Docker Desktop

Makefile Commands

# Show available test commands
make test

# Run all test suites
make test-all

# Run individual test suites
make test-unit
make test-tofu
make test-integration

# Run tests for a specific module
make test-unit MODULE=frontend
make test-tofu MODULE=frontend
make test-integration MODULE=frontend

# Run a single test file directly
bats frontend/deployment/tests/build_context_test.bats
tofu test  # from within a modules directory

Unit Tests (BATS)

Unit tests validate the bash scripts that orchestrate the deployment pipeline. They test individual setup scripts, context building, error handling, and environment configuration.

What to Test

Setup scripts: Validate environment variable handling, error cases, output format
Context builders: Verify JSON structure, required fields, transformations
Error handling: Ensure proper exit codes and error messages
Mock integrations: Test script behavior with mocked CLI tools (aws, np)

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                        test_file.bats                           │
├─────────────────────────────────────────────────────────────────┤
│  setup()                                                        │
│    ├── source assertions.sh      (shared test utilities)        │
│    ├── configure mock CLI tools  (aws, np mocks)                │
│    └── set environment variables                                │
│                                                                 │
│  @test "description" { ... }                                    │
│    ├── run script_under_test                                    │
│    └── assert results                                           │
│                                                                 │
│  teardown()                                                     │
│    └── cleanup                                                  │
└─────────────────────────────────────────────────────────────────┘

Directory Structure

<module>/
├── <component>/
│   └── setup                    # Script under test
└── tests/
    ├── resources/
    │   ├── context.json         # Test fixtures
    │   ├── aws_mocks/           # Mock AWS CLI responses
    │   │   └── aws              # Mock aws executable
    │   └── np_mocks/            # Mock np CLI responses
    │       └── np               # Mock np executable
    └── <component>/
        └── setup_test.bats      # Test file

File Naming Convention

Pattern	Description
`*_test.bats`	BATS test files
`resources/`	Test fixtures and mock data
`*_mocks/`	Mock CLI tool directories

Example Unit Test

#!/usr/bin/env bats
# =============================================================================
# Unit tests for provider/aws/setup script
# =============================================================================

# Setup - runs before each test
setup() {
  TEST_DIR="$(cd "$(dirname "$BATS_TEST_FILENAME")" && pwd)"
  PROJECT_ROOT="$(cd "$TEST_DIR/../../.." && pwd)"
  SCRIPT_PATH="$PROJECT_ROOT/provider/aws/setup"

  # Load shared test utilities
  source "$PROJECT_ROOT/testing/assertions.sh"

  # Initialize required environment variables
  export AWS_REGION="us-east-1"
  export TOFU_PROVIDER_BUCKET="my-terraform-state"
  export TOFU_LOCK_TABLE="terraform-locks"
}

# Teardown - runs after each test
teardown() {
  unset AWS_REGION TOFU_PROVIDER_BUCKET TOFU_LOCK_TABLE
}

# =============================================================================
# Tests
# =============================================================================

@test "fails when AWS_REGION is not set" {
  unset AWS_REGION

  run source "$SCRIPT_PATH"

  assert_equal "$status" "1"
  assert_contains "$output" "AWS_REGION is not set"
}

@test "exports correct TOFU_VARIABLES structure" {
  source "$SCRIPT_PATH"

  local region=$(echo "$TOFU_VARIABLES" | jq -r '.aws_provider.region')
  assert_equal "$region" "us-east-1"
}

@test "appends to existing MODULES_TO_USE" {
  export MODULES_TO_USE="existing/module"

  source "$SCRIPT_PATH"

  assert_contains "$MODULES_TO_USE" "existing/module"
  assert_contains "$MODULES_TO_USE" "provider/aws/modules"
}

Infrastructure Tests (OpenTofu)

Infrastructure tests validate the OpenTofu/Terraform modules in isolation. They verify variable contracts, resource configurations, and module outputs without deploying real infrastructure.

What to Test

Variable validation: Required variables, type constraints, default values
Resource configuration: Correct resource attributes based on inputs
Module outputs: Expected outputs are produced with correct values
Edge cases: Empty values, special characters, boundary conditions

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                      module.tftest.hcl                          │
├─────────────────────────────────────────────────────────────────┤
│  mock_provider "aws" {}        (prevents real API calls)        │
│                                                                 │
│  variables { ... }             (test inputs)                    │
│         │                                                       │
│         ▼                                                       │
│  ┌─────────────────────┐                                        │
│  │  Terraform Module   │       (main.tf, variables.tf, etc.)    │
│  │  under test         │                                        │
│  └─────────┬───────────┘                                        │
│            │                                                    │
│            ▼                                                    │
│  run "test_name" {                                              │
│    command = plan                                               │
│    assert { condition = ... }  (validate outputs/resources)     │
│  }                                                              │
└─────────────────────────────────────────────────────────────────┘

Directory Structure

<module>/
└── modules/
    ├── main.tf
    ├── variables.tf
    ├── outputs.tf
    └── <name>.tftest.hcl    # Test file lives alongside module

File Naming Convention

Pattern	Description
`*.tftest.hcl`	OpenTofu test files
`mock_provider`	Provider mock declarations

Example Infrastructure Test

# =============================================================================
# Unit tests for cloudfront module
# =============================================================================

mock_provider "aws" {}

variables {
  distribution_bucket_name = "my-assets-bucket"
  distribution_app_name    = "my-app-123"
  distribution_s3_prefix   = "/static"

  network_hosted_zone_id = "Z1234567890"
  network_domain         = "example.com"
  network_subdomain      = "app"

  distribution_resource_tags_json = {
    Environment = "test"
  }
}

# =============================================================================
# Test: CloudFront distribution is created with correct origin
# =============================================================================
run "cloudfront_has_correct_s3_origin" {
  command = plan

  assert {
    condition     = aws_cloudfront_distribution.static.origin[0].domain_name != ""
    error_message = "CloudFront distribution must have an S3 origin"
  }
}

# =============================================================================
# Test: Origin Access Control is configured
# =============================================================================
run "oac_is_configured" {
  command = plan

  assert {
    condition     = aws_cloudfront_origin_access_control.static.signing_behavior == "always"
    error_message = "OAC should always sign requests"
  }
}

# =============================================================================
# Test: Custom error responses for SPA routing
# =============================================================================
run "spa_error_responses_configured" {
  command = plan

  assert {
    condition     = length(aws_cloudfront_distribution.static.custom_error_response) > 0
    error_message = "SPA should have custom error responses for client-side routing"
  }
}

Integration Tests

Integration tests validate the complete deployment workflow end-to-end. They run in a containerized environment with mocked cloud services, testing the entire pipeline from context building through infrastructure provisioning.

What to Test

Complete workflows: Full deployment and destruction cycles
Service interactions: AWS services, nullplatform API calls
Resource creation: Verify infrastructure is created correctly
Cleanup: Ensure resources are properly destroyed

Architecture

┌─ Host Machine ──────────────────────────────────────────────────────────────┐
│                                                                             │
│   make test-integration                                                     │
│         │                                                                   │
│         ▼                                                                   │
│   run_integration_tests.sh ──► docker compose up                            │
│                                                                             │
└─────────────────────────────────┬───────────────────────────────────────────┘
                                  │
┌─ Docker Network ────────────────┴───────────────────────────────────────────┐
│                                                                             │
│  ┌─ Test Container ───────────────────────────────────────────────────────┐ │
│  │                                                                        │ │
│  │   BATS Tests ──► np CLI ──────────────────┐                            │ │
│  │       │                                   │                            │ │
│  │       ▼                                   ▼                            │ │
│  │   OpenTofu                          Nginx (HTTPS)                      │ │
│  │       │                                   │                            │ │
│  └───────┼───────────────────────────────────┼────────────────────────────┘ │
│          │                                   │                              │
│          ▼                                   ▼                              │
│  ┌─ Mock Services ────────────────────────────────────────────────────────┐ │
│  │                                                                        │ │
│  │   LocalStack (4566)          Moto (5555)          Smocker (8081)       │ │
│  │   ├── S3                     └── CloudFront       └── nullplatform API │ │
│  │   ├── Route53                                                          │ │
│  │   ├── DynamoDB                                                         │ │
│  │   ├── IAM                                                              │ │
│  │   └── STS                                                              │ │
│  │                                                                        │ │
│  └────────────────────────────────────────────────────────────────────────┘ │
│                                                                             │
└─────────────────────────────────────────────────────────────────────────────┘

Service Components

Service	Purpose	Port
LocalStack	AWS service emulation (S3, Route53, DynamoDB, IAM, STS, ACM)	4566
Moto	CloudFront emulation (not supported in LocalStack free tier)	5555
Smocker	nullplatform API mocking	8080/8081
Nginx	HTTPS reverse proxy for np CLI	8443

Directory Structure

<module>/
└── tests/
    └── integration/
        ├── cloudfront_lifecycle_test.bats   # Integration test
        ├── localstack/
        │   └── provider_override.tf          # LocalStack-compatible provider config
        └── mocks/
            └── <api_endpoint>/
                └── response.json             # Mock API responses

File Naming Convention

Pattern	Description
`*_test.bats`	Integration test files
`localstack/`	LocalStack-compatible Terraform overrides
`mocks/`	API mock response files

Example Integration Test

#!/usr/bin/env bats
# =============================================================================
# Integration test: CloudFront Distribution Lifecycle
# =============================================================================

setup_file() {
  source "${PROJECT_ROOT}/testing/integration_helpers.sh"

  # Clear any existing mocks
  clear_mocks

  # Create AWS prerequisites in LocalStack
  aws_local s3api create-bucket --bucket assets-bucket
  aws_local s3api create-bucket --bucket tofu-state-bucket
  aws_local dynamodb create-table \
    --table-name tofu-locks \
    --attribute-definitions AttributeName=LockID,AttributeType=S \
    --key-schema AttributeName=LockID,KeyType=HASH \
    --billing-mode PAY_PER_REQUEST
  aws_local route53 create-hosted-zone \
    --name example.com \
    --caller-reference "test-$(date +%s)"
}

teardown_file() {
  source "${PROJECT_ROOT}/testing/integration_helpers.sh"
  clear_mocks
}

setup() {
  source "${PROJECT_ROOT}/testing/integration_helpers.sh"

  clear_mocks
  load_context "tests/resources/context.json"

  export TOFU_PROVIDER="aws"
  export TOFU_PROVIDER_BUCKET="tofu-state-bucket"
  export AWS_REGION="us-east-1"
}

# =============================================================================
# Test: Create Infrastructure
# =============================================================================
@test "create infrastructure deploys S3, CloudFront, and Route53 resources" {
  # Setup API mocks
  mock_request "GET" "/provider" "mocks/provider_success.json"

  # Run the deployment workflow
  run_workflow "deployment/workflows/initial.yaml"

  # Verify resources were created
  assert_s3_bucket_exists "assets-bucket"
  assert_cloudfront_exists "Distribution for my-app"
  assert_route53_record_exists "app.example.com" "A"
}

# =============================================================================
# Test: Destroy Infrastructure
# =============================================================================
@test "destroy infrastructure removes CloudFront and Route53 resources" {
  mock_request "GET" "/provider" "mocks/provider_success.json"

  run_workflow "deployment/workflows/delete.yaml"

  assert_cloudfront_not_exists "Distribution for my-app"
  assert_route53_record_not_exists "app.example.com" "A"
}

Test Helpers Reference

Viewing Available Helpers

Both helper libraries include a test_help function that displays all available utilities:

# View unit test helpers
source testing/assertions.sh && test_help

# View integration test helpers
source testing/integration_helpers.sh && test_help

Unit Test Assertions (`testing/assertions.sh`)

Function	Description
`assert_equal "$actual" "$expected"`	Assert two values are equal
`assert_contains "$haystack" "$needle"`	Assert string contains substring
`assert_not_empty "$value" ["$name"]`	Assert value is not empty
`assert_empty "$value" ["$name"]`	Assert value is empty
`assert_file_exists "$path"`	Assert file exists
`assert_directory_exists "$path"`	Assert directory exists
`assert_json_equal "$actual" "$expected"`	Assert JSON structures are equal

Integration Test Helpers (`testing/integration_helpers.sh`)

AWS Commands

Function	Description
`aws_local <args>`	Execute AWS CLI against LocalStack
`aws_moto <args>`	Execute AWS CLI against Moto (CloudFront)

Workflow Execution

Function	Description
`run_workflow "$path"`	Run a nullplatform workflow file

Context Management

Function	Description
`load_context "$path"`	Load context JSON into `$CONTEXT`
`override_context "$key" "$value"`	Override a value in current context

API Mocking

Function	Description
`clear_mocks`	Clear all mocks, set up defaults
`mock_request "$method" "$path" "$file"`	Mock API request with file response
`mock_request "$method" "$path" $status '$body'`	Mock API request inline
`assert_mock_called "$method" "$path"`	Assert mock was called

AWS Assertions

Function	Description
`assert_s3_bucket_exists "$bucket"`	Assert S3 bucket exists
`assert_s3_bucket_not_exists "$bucket"`	Assert S3 bucket doesn't exist
`assert_cloudfront_exists "$comment"`	Assert CloudFront distribution exists
`assert_cloudfront_not_exists "$comment"`	Assert CloudFront distribution doesn't exist
`assert_route53_record_exists "$name" "$type"`	Assert Route53 record exists
`assert_route53_record_not_exists "$name" "$type"`	Assert Route53 record doesn't exist
`assert_dynamodb_table_exists "$table"`	Assert DynamoDB table exists

Writing New Tests

Unit Test Checklist

Create test file: <module>/tests/<component>/<name>_test.bats
Add setup() function that sources testing/assertions.sh
Set up required environment variables and mocks
Write tests using @test "description" { ... } syntax
Use run to capture command output and exit status
Assert with helper functions or standard bash conditionals

Infrastructure Test Checklist

Create test file: <module>/modules/<name>.tftest.hcl
Add mock_provider "aws" {} to avoid real API calls
Define variables {} block with test inputs
Write run "test_name" { ... } blocks with assertions
Use command = plan to validate without applying

Integration Test Checklist

Create test file: <module>/tests/integration/<name>_test.bats
Add setup_file() to create prerequisites in LocalStack
Add setup() to configure mocks and context per test
Add teardown_file() to clean up
Create localstack/provider_override.tf for LocalStack-compatible provider
Create mock response files in mocks/ directory
Use run_workflow to execute deployment workflows
Assert with AWS assertion helpers

Extending Test Helpers

Adding New Assertions

Add the function to the appropriate helper file:
- testing/assertions.sh for unit test helpers
- testing/integration_helpers.sh for integration test helpers
Follow the naming convention: assert_<condition> for assertions
Update the test_help function to document your new helper:

# Example: Adding a new assertion to assertions.sh

# Add the function
assert_file_contains() {
  local file="$1"
  local content="$2"
  if ! grep -q "$content" "$file" 2>/dev/null; then
    echo "Expected file '$file' to contain: $content"
    return 1
  fi
}

# Update test_help() - add to the appropriate section
test_help() {
  cat <<'EOF'
...
FILE SYSTEM ASSERTIONS
----------------------
  assert_file_exists "<path>"
      Assert a file exists.

  assert_file_contains "<path>" "<content>"     # <-- Add documentation
      Assert a file contains specific content.
...
EOF
}

Test your new helper before committing

Helper Design Guidelines

Return 0 on success, non-zero on failure
Print descriptive error messages on failure
Keep functions focused and single-purpose
Use consistent naming conventions
Document parameters and usage in test_help()

Troubleshooting

Common Issues

Issue	Solution
`bats: command not found`	Install bats-core: `brew install bats-core`
`tofu: command not found`	Install OpenTofu: `brew install opentofu`
Integration tests hang	Check Docker is running, increase timeout
LocalStack services not ready	Wait for health checks, check Docker logs
Mock not being called	Verify mock path matches exactly, check Smocker logs

Debugging Integration Tests

# View LocalStack logs
docker logs integration-localstack

# View Smocker mock history
curl http://localhost:8081/history | jq

# Run tests with verbose output
bats --show-output-of-passing-tests frontend/deployment/tests/integration/*.bats

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File metadata and controls

Testing Guide

Table of Contents

Quick Start

Test Layers Overview

Running Tests

Prerequisites

Makefile Commands

Unit Tests (BATS)

What to Test

Architecture

Directory Structure

File Naming Convention

Example Unit Test

Infrastructure Tests (OpenTofu)

What to Test

Architecture

Directory Structure

File Naming Convention

Example Infrastructure Test

Integration Tests

What to Test

Architecture

Service Components

Directory Structure

File Naming Convention

Example Integration Test

Test Helpers Reference

Viewing Available Helpers

Unit Test Assertions (testing/assertions.sh)

Integration Test Helpers (testing/integration_helpers.sh)

AWS Commands

Workflow Execution

Context Management

API Mocking

AWS Assertions

Writing New Tests

Unit Test Checklist

Infrastructure Test Checklist

Integration Test Checklist

Extending Test Helpers

Adding New Assertions

Helper Design Guidelines

Troubleshooting

Common Issues

Debugging Integration Tests

Additional Resources

Unit Test Assertions (`testing/assertions.sh`)

Integration Test Helpers (`testing/integration_helpers.sh`)