# Testing Guide

This project uses modern Go testing practices for 2025, focusing on reliability, maintainability, and efficiency.

## Testing Stack

- **Ginkgo**: BDD testing framework for expressive, readable test specifications
- **Gomega**: Matcher library for flexible assertions
- **Testify**: Additional assertion helpers and mocking capabilities
- **TestContainers**: For integration tests with real dependencies (planned)

## Test Structure

```
internal/
├── service/
│   ├── *_test.go          # Unit tests for services
│   └── ...
├── testutils/
│   └── fixtures.go        # Test data fixtures
└── ...
```

## Running Tests

### Unit Tests

```bash
# Run all tests
go test ./...

# Run specific package
go test ./internal/service

# Run with coverage
go test -cover ./internal/service

# Run with verbose output
go test -v ./internal/service
```

### BDD Tests with Ginkgo

```bash
# Install ginkgo CLI
go install github.com/onsi/ginkgo/v2/ginkgo

# Run tests
ginkgo ./internal/service

# Watch mode
ginkgo watch ./internal/service
```

## Writing Tests

### Unit Tests with Ginkgo/Gomega

```go
package service_test

import (
    . "github.com/onsi/ginkgo/v2"
    . "github.com/onsi/gomega"
    "your-project/internal/service"
)

var _ = Describe("MyService", func() {
    var svc *service.MyService

    BeforeEach(func() {
        svc = service.NewMyService()
    })

    Describe("DoSomething", func() {
        Context("with valid input", func() {
            It("returns expected result", func() {
                result := svc.DoSomething("input")
                Expect(result).To(Equal("expected"))
            })
        })
    })
})
```

### Using Test Utilities

The `internal/testutils` package provides rich, reusable test fixtures and builders:

### Builders for Flexible Test Data

```go
// Fluent interface for creating test data
rf := testutils.NewResourceFlowBuilder().
    WithType(domain.TypeWater).
    WithQuantity(500, "liters").
    WithDirection(domain.DirectionInput).
    Build()

business := testutils.NewBusinessBuilder().
    WithNACE("C20.11").
    WithCertifications([]string{"ISO 9001"}).
    WithHighTrustScore().
    Build()
```

### Semantic Factory Functions

```go
// Pre-configured test data
validFlow := testutils.CreateValidHeatResourceFlow()
incompleteFlow := testutils.CreateIncompleteResourceFlow()
lowQualityFlow := testutils.CreateLowQualityResourceFlow()

highTrustBusiness := testutils.CreateHighTrustBusinessEntity()
validMatch := testutils.CreateValidMatchProposal()
```

### Test Data Suite

```go
// Complete suite for comprehensive testing
suite := testutils.NewTestDataSuite()
// Access: suite.ValidHeatFlow, suite.IncompleteFlow, etc.
```

### Deterministic Testing

```go
// Fixed time for consistent results
fixedTime := testutils.FixedTime()
// Use in assertions or data creation
```

### Mocking with GoMock

```go
// Generate mocks
mockgen -source=internal/repository/interface.go -destination=internal/repository/mock_interface.go

// Use in tests
mockRepo := &mock_interface.MockRepository{}
mockRepo.EXPECT().GetByID("id").Return(expectedResult, nil)
```

## Test Categories

- **Unit Tests**: Test individual functions/methods in isolation
- **Integration Tests**: Test component interactions (planned with TestContainers)
- **BDD Tests**: Behavior-driven tests for business logic

## Best Practices

1. **Test Naming**: Use descriptive names that explain the behavior
2. **Arrange-Act-Assert**: Structure tests clearly
3. **Table-Driven Tests**: For multiple test cases
4. **Parallel Execution**: Tests run in parallel by default
5. **Fixtures**: Use shared test data for consistency
6. **Coverage**: Aim for >80% coverage on critical paths

## Continuous Integration

Tests are designed to run efficiently in CI/CD pipelines with:

- Fast execution (<30s for unit tests)
- No external dependencies for unit tests
- Deterministic results
- Clear failure reporting