Terraform Test Generator

Generate Terraform native tests (.tftest.hcl) following project conventions.

Test Categories

This project uses two types of tests:

1. Variable Validation Tests

For variables with validation blocks. Test boundary values:

• •Valid minimum/maximum values
• •Invalid values below/above boundaries
• •Valid enum values
• •Invalid enum values

2. Conditional Resource Tests

For resources with count or dynamic blocks. Test:

• •Resource creation when enabled (count > 0)
• •Resource absence when disabled (count = 0)
• •Output values reflecting conditional state

Test File Structure

# [Test Category] Tests
# [Description of what is being tested]

# -----------------------------------------------------------------------------
# Common Test Configuration
# -----------------------------------------------------------------------------
mock_provider "google" {
  override_data {
    target = module.iam_bindings.data.google_project.project
    values = {
      project_id = "test-project"
      number     = "123456789012"
    }
  }
}

variables {
  project_id      = "test-project"
  region          = "asia-northeast1"
  environment     = "dev"
  project_name    = "events"
  container_image = "gcr.io/test/image:latest"
}
# -----------------------------------------------------------------------------

# =============================================================================
# [Variable/Feature Name]: [Constraint Description]
# =============================================================================

run "test_name" {
  command = plan

  variables {
    # Override specific variables for this test
  }

  # For validation tests expecting failure:
  # expect_failures = [var.variable_name]

  # For conditional resource tests:
  assert {
    condition     = <expression>
    error_message = "Description of expected behavior"
  }
}

Instructions

1. •

   Analyze the Terraform configuration:

   • •Find variables with validation blocks in variables.tf
   • •Find resources with count or dynamic blocks in modules
2. •

   For Variable Validation Tests:

   hcl

   # Valid boundary test
   run "variable_valid_min" {
     command = plan
     variables { variable_name = <min_valid_value> }
   }
   
   # Invalid boundary test
   run "variable_invalid_below_min" {
     command = plan
     variables { variable_name = <below_min_value> }
     expect_failures = [var.variable_name]
   }
   

3. •

   For Conditional Resource Tests:

   hcl

   run "feature_enabled" {
     command = plan
     variables { enable_feature = true }
   
     assert {
       condition     = output.related_output != null
       error_message = "Output should be set when feature is enabled"
     }
   }
   
   run "feature_disabled" {
     command = plan
     variables { enable_feature = false }
   
     assert {
       condition     = output.related_output == null
       error_message = "Output should be null when feature is disabled"
     }
   }
   

4. •

   Test Location: tests/*.tftest.hcl

5. •

   Run Tests:

   bash

   cd architectures/<pattern>/gcp
   terraform init -backend=false
   terraform test -test-directory=tests
   

Naming Conventions

• •Test file: <category>.tftest.hcl (e.g., variables_validation.tftest.hcl)
• •Run block: <variable>_<valid|invalid>_<description> (e.g., environment_invalid_test)
• •Use snake_case for all identifiers

Key Points

• •Use command = plan (not apply) for all tests
• •Use mock_provider to avoid real API calls
• •Each test file has its own Common Test Configuration (not shared)
• •Test only what matters: validation rules and conditional logic
• •Keep tests focused and minimal