Test Structure

Test Structure Setup

Establish comprehensive testing infrastructure with optimal framework configuration, logical directory organization, efficient fixture management, and reusable test utilities. This skill is Phase 1 of the 8-phase testing methodology and provides the foundation for all subsequent testing activities.

When to Use This Skill

Use this skill when you need to:

• Start testing in a new project from scratch
• Add testing infrastructure to an existing codebase
• Restructure or improve existing test organization
• Configure a testing framework (pytest, Jest, JUnit, xUnit, Go testing)
• Set up test discovery, fixtures, and utilities
• Establish testing standards for a team
• Migrate from one testing framework to another

Trigger phrases: "set up tests", "configure testing", "create test structure", "initialize tests", "test infrastructure", "pytest setup", "Jest configuration", "JUnit setup", "testing framework"

What This Skill Does

For All Languages

1. Framework Selection & Configuration

   • Analyze project requirements for framework selection
   • Configure framework settings and plugins
   • Set up test discovery rules
   • Enable parallel test execution
   • Configure output formats and reporting

2. Directory Structure Design

   • Create standardized test directory layout
   • Separate test types (unit, integration, e2e)
   • Establish naming conventions
   • Set up resource directories for test data
   • Configure module initialization files

3. Fixture Infrastructure

   • Establish fixture hierarchy and scopes
   • Create fixture factories for complex objects
   • Implement shared fixtures across test modules
   • Document fixture usage patterns
   • Set up fixture cleanup and teardown

4. Test Utilities & Helpers

   • Create common assertion helpers
   • Implement test data generators
   • Define custom decorators/annotations
   • Establish shared base classes
   • Document utility functions

Language-Specific Features

Python (pytest)

• Framework: pytest 8.x with plugins (pytest-cov, pytest-xdist, pytest-mock)
• Configuration: pyproject.toml or pytest.ini
• Fixtures: conftest.py hierarchy with scoped fixtures
• Markers: Custom markers for test categorization

# pyproject.toml
[tool.pytest.ini_options]
minversion = "8.0"
testpaths = ["tests"]
python_files = ["test_*.py", "*_test.py"]
python_classes = ["Test*"]
python_functions = ["test_*"]
addopts = [
    "-ra",
    "--strict-markers",
    "--strict-config",
    "-v",
]
markers = [
    "unit: Unit tests (fast, isolated)",
    "integration: Integration tests (may use external resources)",
    "e2e: End-to-end tests (full system)",
    "slow: Tests that take >1s",
]

# Directory structure
tests/
├── conftest.py              # Root fixtures
├── unit/
│   ├── conftest.py          # Unit-specific fixtures
│   ├── test_models.py
│   └── test_services.py
├── integration/
│   ├── conftest.py
│   └── test_api.py
└── e2e/
    └── test_workflows.py

JavaScript/TypeScript (Jest)

• Framework: Jest 29.x with TypeScript support
• Configuration: jest.config.js or package.json
• Setup Files: setupTests.js for global configuration
• Mocking: Built-in mock functions and module mocking

// jest.config.js
module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'node',
  roots: ['<rootDir>/src', '<rootDir>/tests'],
  testMatch: ['**/__tests__/**/*.ts', '**/*.test.ts', '**/*.spec.ts'],
  collectCoverageFrom: ['src/**/*.ts', '!src/**/*.d.ts'],
  coverageThreshold: {
    global: { branches: 80, functions: 80, lines: 80, statements: 80 }
  },
  setupFilesAfterEnv: ['<rootDir>/tests/setupTests.ts'],
  moduleNameMapper: {
    '^@/(.*)$': '<rootDir>/src/$1'
  }
};

// Directory structure
tests/
├── setupTests.ts            # Global setup
├── helpers/
│   ├── factories.ts         # Test data factories
│   └── mocks.ts             # Shared mocks
├── unit/
│   └── services.test.ts
└── integration/
    └── api.test.ts

Java (JUnit 5)

• Framework: JUnit 5 (Jupiter) with Mockito
• Configuration: pom.xml or build.gradle
• Extensions: Custom extensions for lifecycle management
• Nested Tests: Organized test hierarchies

// pom.xml dependencies
<dependencies>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter</artifactId>
        <version>5.10.0</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.mockito</groupId>
        <artifactId>mockito-junit-jupiter</artifactId>
        <version>5.7.0</version>
        <scope>test</scope>
    </dependency>
</dependencies>

// Directory structure
src/
├── main/java/com/example/
│   └── service/
└── test/java/com/example/
    ├── unit/
    │   └── service/
    │       └── UserServiceTest.java
    ├── integration/
    │   └── api/
    └── fixtures/
        └── TestDataFactory.java

C# (xUnit/NUnit)

• Framework: xUnit 2.x or NUnit 3.x
• Configuration: .csproj with test settings
• Fixtures: IClassFixture for shared context
• Theory: Data-driven tests with InlineData

// MyProject.Tests.csproj
<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    <IsPackable>false</IsPackable>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="xunit" Version="2.6.0" />
    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.0" />
    <PackageReference Include="Moq" Version="4.20.0" />
    <PackageReference Include="FluentAssertions" Version="6.12.0" />
    <PackageReference Include="coverlet.collector" Version="6.0.0" />
  </ItemGroup>
</Project>

// Directory structure
tests/
├── MyProject.Tests/
│   ├── Unit/
│   │   └── Services/
│   ├── Integration/
│   └── Fixtures/
│       └── DatabaseFixture.cs

Go (testing package)

• Framework: Built-in testing package with testify
• Configuration: go.mod for dependencies
• Table-Driven: Idiomatic table-driven tests
• Subtests: t.Run for organized test cases

// go.mod
module example.com/myproject

require (
    github.com/stretchr/testify v1.8.4
    github.com/golang/mock v1.6.0
)

// Directory structure (tests alongside code)
pkg/
├── service/
│   ├── user.go
│   └── user_test.go          # Unit tests
├── integration/
│   └── api_test.go           # Integration tests
└── testutil/
    ├── fixtures.go           # Test fixtures
    └── mocks/                 # Generated mocks

C (Unity/CUnit)

• Framework: Unity or CUnit for embedded/systems
• Configuration: CMakeLists.txt or Makefile
• Fixtures: setUp/tearDown functions
• Test Runners: Custom or CTest integration

// CMakeLists.txt
cmake_minimum_required(VERSION 3.14)
project(myproject C)

enable_testing()

# Unity test framework
add_subdirectory(vendor/Unity)

# Test executable
add_executable(test_runner
    tests/test_main.c
    tests/test_module.c
    src/module.c
)
target_link_libraries(test_runner unity)

add_test(NAME unit_tests COMMAND test_runner)

// Directory structure
project/
├── src/
│   └── module.c
├── include/
│   └── module.h
├── tests/
│   ├── test_main.c           # Test runner
│   ├── test_module.c         # Module tests
│   └── fixtures/
│       └── test_data.h
└── vendor/
    └── Unity/

C++ (GoogleTest/Catch2)

• Framework: GoogleTest (gtest) or Catch2
• Configuration: CMakeLists.txt with FetchContent
• Fixtures: Test fixtures with SetUp/TearDown
• Parameterized: INSTANTIATE_TEST_SUITE_P

// CMakeLists.txt
cmake_minimum_required(VERSION 3.14)
project(myproject CXX)

set(CMAKE_CXX_STANDARD 17)
enable_testing()

include(FetchContent)
FetchContent_Declare(
    googletest
    GIT_REPOSITORY https://github.com/google/googletest.git
    GIT_TAG v1.14.0
)
FetchContent_MakeAvailable(googletest)

add_executable(tests
    tests/test_main.cpp
    tests/test_module.cpp
)
target_link_libraries(tests gtest_main gmock)
include(GoogleTest)
gtest_discover_tests(tests)

// Directory structure
project/
├── src/
│   └── module.cpp
├── include/
│   └── module.hpp
├── tests/
│   ├── test_main.cpp
│   ├── unit/
│   │   └── test_module.cpp
│   └── fixtures/
│       └── test_fixtures.hpp

Prerequisites

• Source code repository with clear module structure
• Build system configured (pip, npm, Maven, MSBuild, Go modules, CMake)
• Understanding of project architecture
• Decision on test types needed (unit, integration, e2e)

Instructions

Step 1: Analyze Project Structure

1. Examine Source Code Organization

   # Get directory structure
   tree -L 3 -I 'node_modules|venv|.venv|__pycache__|target|build|bin|obj'
   

2. Identify Modules to Test

   • List main source directories
   • Identify core business logic
   • Note external dependencies
   • Map API endpoints or interfaces

3. Document Current Test State

   • Check for existing tests
   • Review current test configuration
   • Note coverage gaps

Step 2: Select and Configure Framework

1. Choose Framework (if not already decided)

   • Python: pytest (recommended)
   • JavaScript/TypeScript: Jest
   • Java: JUnit 5
   • C#: xUnit or NUnit
   • Go: testing + testify
   • C: Unity or CUnit
   • C++: GoogleTest or Catch2

2. Install Framework and Plugins

   Python:

   pip install pytest pytest-cov pytest-xdist pytest-mock pytest-asyncio
   

   JavaScript:

   npm install --save-dev jest @types/jest ts-jest
   

   Java (Maven):

   <dependency>
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter</artifactId>
       <version>5.10.0</version>
       <scope>test</scope>
   </dependency>
   

3. Create Configuration File

   • Add framework-specific configuration
   • Configure test discovery patterns
   • Set up parallel execution
   • Define output formats

Step 3: Create Directory Structure

1. Create Test Directories

   # Python/JavaScript/Go
   mkdir -p tests/unit tests/integration tests/e2e tests/fixtures
   
   # Java
   mkdir -p src/test/java/com/example/unit
   mkdir -p src/test/java/com/example/integration
   
   # C#
   mkdir -p tests/MyProject.Tests/Unit
   mkdir -p tests/MyProject.Tests/Integration
   

2. Add Initialization Files

   • Python: __init__.py in each test directory
   • JavaScript: index.ts exports if needed
   • Java: Package structure matching source

3. Create Fixture Directories

   • Test data files location
   • Mock response files
   • Configuration samples

Step 4: Set Up Fixtures and Utilities

1. Create Root Fixture File

   Python (conftest.py):

   import pytest
   from typing import Generator
   
   @pytest.fixture(scope="session")
   def app_config() -> dict:
       """Application configuration for tests."""
       return {
           "database_url": "sqlite:///:memory:",
           "api_key": "test-key",
           "debug": True
       }
   
   @pytest.fixture
   def sample_user() -> dict:
       """Sample user data for tests."""
       return {
           "id": 1,
           "name": "Test User",
           "email": "test@example.com"
       }
   

   JavaScript (setupTests.ts):

   import { jest } from '@jest/globals';
   
   // Global test setup
   beforeAll(() => {
     process.env.NODE_ENV = 'test';
   });
   
   // Reset mocks between tests
   afterEach(() => {
     jest.clearAllMocks();
   });
   
   // Test utilities
   export const createMockUser = () => ({
     id: 1,
     name: 'Test User',
     email: 'test@example.com'
   });
   

2. Create Test Data Factories

   • Factory functions for complex objects
   • Random data generation
   • Consistent test data across tests

3. Create Custom Assertions

   • Domain-specific assertion helpers
   • Improved error messages
   • Complex validation shortcuts

Step 5: Create Sample Tests

1. Create First Unit Test

   Python:

   # tests/unit/test_example.py
   import pytest
   
   class TestExample:
       """Example test class demonstrating structure."""
   
       def test_addition(self):
           """Test basic addition."""
           # Arrange
           a, b = 2, 3
   
           # Act
           result = a + b
   
           # Assert
           assert result == 5
   
       @pytest.mark.parametrize("input,expected", [
           (1, 1),
           (2, 4),
           (3, 9),
       ])
       def test_square(self, input: int, expected: int):
           """Test square calculation with multiple inputs."""
           assert input ** 2 == expected
   

2. Verify Test Discovery

   # Python
   pytest --collect-only
   
   # JavaScript
   jest --listTests
   
   # Java
   mvn test -Dtest=*Test
   
   # Go
   go test -v -list '.*'
   

3. Run Tests

   # Python
   pytest -v
   
   # JavaScript
   npm test
   
   # Java
   mvn test
   
   # C#
   dotnet test
   
   # Go
   go test ./...
   

Step 6: Document Testing Standards

1. Create Testing Guide

   • Naming conventions
   • Directory structure explanation
   • Fixture usage patterns
   • Running tests locally
   • CI/CD integration

2. Define Quality Standards

   • Minimum coverage requirements (80%+)
   • Test execution time limits (<1s for unit tests)
   • Required test types per feature
   • Review checklist for tests

Output Structure

tests/
├── conftest.py / setupTests.ts / fixtures/     # Shared fixtures
├── unit/                                        # Unit tests
│   ├── test_models.py / models.test.ts
│   └── test_services.py / services.test.ts
├── integration/                                 # Integration tests
│   └── test_api.py / api.test.ts
├── e2e/                                         # End-to-end tests
│   └── test_workflows.py / workflows.test.ts
├── fixtures/                                    # Test data
│   ├── sample_data.json
│   └── mock_responses/
└── helpers/                                     # Test utilities
    ├── factories.py / factories.ts
    └── assertions.py / assertions.ts

Quality Checklist

Before completing test structure setup, verify:

• Framework installed and configured correctly
• Configuration file created (pytest.ini, jest.config.js, etc.)
• Test directories created with proper naming
• Initialization files added where needed
• Root fixture/setup file created
• Sample test runs successfully
• Test discovery finds all test files
• Parallel execution configured (if applicable)
• Coverage reporting configured
• Testing guide documented
• CI/CD integration prepared

Common Issues and Solutions

Issue: Tests not discovered

Solution: Verify naming conventions match framework patterns. Python tests must start with test_, JavaScript tests must end with .test.ts or .spec.ts.

Issue: Import errors in tests

Solution: Ensure proper package structure with __init__.py files (Python) or module resolution configured (JavaScript/TypeScript).

Issue: Fixtures not found

Solution: Check fixture file location (conftest.py must be in tests/ or parent directory), verify fixture scope matches usage.

Issue: Slow test execution

Solution: Configure parallel execution (pytest-xdist, Jest workers), separate slow tests with markers.

Success Criteria

After using this skill, you should have:

• Complete test infrastructure configured
• Clear directory structure for all test types
• Reusable fixtures and utilities created
• Sample tests passing successfully
• Documentation for testing standards
• CI/CD-ready test configuration

Related Skills

• unit-tests - Generate comprehensive unit tests (Phase 2)
• test-cases - Create integration and E2E tests (Phase 3)
• mocks-fixtures - Build test doubles and fixtures (Phase 4)
• cicd-integration - Configure test automation (Phase 6)

Tools by Language

Python

• pytest: Primary test framework
• pytest-cov: Coverage reporting
• pytest-xdist: Parallel execution
• pytest-mock: Mocking integration

JavaScript/TypeScript

• Jest: Primary test framework
• ts-jest: TypeScript support
• @testing-library: DOM testing utilities

Java

• JUnit 5: Primary test framework
• Mockito: Mocking framework
• JaCoCo: Coverage reporting

C#

• xUnit/NUnit: Test frameworks
• Moq: Mocking framework
• Coverlet: Coverage collection

Go

• testing: Built-in package
• testify: Assertions and mocking
• gomock: Interface mocking

C/C++

• Unity/CUnit: C test frameworks
• GoogleTest: C++ test framework
• CMake/CTest: Build and test integration

Version: 1.0.0 Last Updated: December 2025 Based on: AI Templates tests_generation/test_structure/

Iterative Refinement Strategy

This skill is optimized for an iterative approach:

1. Execute: Perform the core steps defined above.
2. Review: Critically analyze the output (coverage, quality, completeness).
3. Refine: If targets aren't met, repeat the specific implementation steps with improved context.
4. Loop: Continue until the definition of done is satisfied.