# Testing Workflow Guide for YeetGeese

This document provides a structured approach to testing Godot 4.x games, with specific focus on the tower defense mechanics of YeetGeese. It covers what to test, how to structure tests, and debugging failed tests.

---

## Table of Contents

1. [Testing Philosophy](#testing-philosophy)
2. [Test Organization](#test-organization)
3. [Test Categories](#test-categories)
4. [Writing Tests](#writing-tests)
5. [Debugging Failed Tests](#debugging-failed-tests)
6. [CI Integration](#ci-integration)

---

## Testing Philosophy

### Why Test?

- **Regression prevention:** Catch unintended side effects from changes
- **Documentation by example:** Tests serve as usage examples
- **Design validation:** Ensure architecture matches intent
- **Confidence for refactoring:** Safe to reorganize code when tested

### What AI Can Help With

AI can:
- Generate boilerplate test scaffolding
- Suggest edge cases and boundary conditions
- Write mock implementations for complex systems
- Explain Godot testing framework capabilities

### What AI Cannot Handle

AI should NOT:
- Design game mechanics or balance (human domain)
- Make subjective quality-of-life judgments
- Replace manual playtesting of actual gameplay feel
- Generate test data for art assets (no AI-generated art rule applies)

---

## Test Organization

### Directory Structure

```
tests/
├── core/               # Autoloads and global state tests
│   ├── wave_progression_test.gd
│   └── currency_manager_test.gd
├── towers/             # Tower behavior tests
│   ├── tower_base_test.gd
│   ├── projectile_spawner_test.gd
│   └── target_finder_test.gd
├── enemies/            # Enemy system tests
│   ├── enemy_mob_test.gd
│   ├── navigation_system_test.gd
│   └── spawner_test.gd
├── projectiles/        # Projectile handling tests
│   ├── goose_projectile_test.gd
│   └── impact_handler_test.gd
├── ui/                 # HUD and menu tests
│   ├── health_bar_test.gd
│   └── currency_display_test.gd
├── utils/              # Utility functions
│   └── math_utils_test.gd
└── integration/        # Cross-system tests
    ├── wave_complete_sequence_test.gd
    └── tower_placement_integration_test.gd
```

### Naming Conventions

- Files: `<system>_test.gd` (e.g., `tower_base_test.gd`)
- Functions: `func test_<behavior_description>()` (e.g., `func test_fire_rate_scales_with_level()`)
- Assertions: Use descriptive names like `assert_equal`, `assert_signal_emitted`, `assert_no_error`

---

## Test Categories

### Unit Tests

Test individual functions or methods in isolation.

**Example:** Testing a tower's fire rate calculation

```gdscript
@tool
extends Node

func test_fire_rate_calculation(tower: Node) -> void:
    assert_equal(tower.fire_rate, 1.0)
    
    # Modify tower level
    tower.tower_level = 2
    
    # Verify fire rate changed appropriately
    assert_greater(tower.fire_rate, 1.0)
    assert_less(tower.fire_rate, 2.0)

func test_damage_scaling_by_tower_level(tower: Node) -> void:
    tower.tower_level = 3
    
    var initial_damage = tower.get_damage_at_current_level()
    tower.tower_level = 5
    
    # Verify damage increased with level
    assert_greater(tower.get_damage_at_current_level(), initial_damage)
```

**When to use:**
- Testing pure logic (math, state transitions)
- Testing Resource loading and property access
- Testing signal emission patterns

---

### Integration Tests

Test interactions between multiple systems.

**Example:** Testing the full projectile launch sequence

```gdscript
@tool
extends Node

func test_projectile_launch_sequence() -> void:
    # Arrange: Create mock tower and target
    var tower := _create_mock_tower()
    var target := _create_mock_target()
    
    # Act: Fire at target
    tower.fire_at(target)
    
    # Assert: Verify projectile spawned in correct state
    assert_true(tower.projectile_count == 1)
    assert_equal(tower.projectiles[0].source_node, tower.$ProjectileSpawner)
```

**When to use:**
- Testing scene hierarchies with multiple nodes
- Verifying signal connections between systems
- Validating Godot's built-in component behavior (e.g., RigidBody2D movement)

---

### Regression Tests

Tests added when a bug is fixed to ensure it doesn't return.

**Example:** Preventing physics tunneling after a collision fix

```gdscript
@tool
extends Node

func test_projectile_collision_prevents_tunneling() -> void:
    # Scenario: Goose projectile moving at high speed
    var projectile := _create_goose_with_velocity(100.0)
    var enemy := _create_enemy_with_small_hitbox()
    
    # Act: Move projectile toward enemy's hitbox
    projectile.yeet_from(projectile.position, enemy.position)
    
    # Assert: Projectile detected collision on this frame
    assert_signal_emitted(projectile, 'collision_detected')
```

**When to use:**
- After fixing a critical bug
- When performance regression occurs
- To validate edge case handling

---

## Writing Tests

### Test Function Template

```gdscript
@tool
extends Node

func test_<behavior_under_test>() -> void:
    # Arrange: Setup the scenario
    var <subject> := _create_mock_<subject>()
    
    # Act: Execute the action being tested
    <subject>.<method_or_event>()
    
    # Assert: Verify expected behavior
    assert_true(<condition_1>)
    assert_false(<condition_2>)
    assert_signal_emitted(<signal_source>, '<signal_name>')
```

### Available Assertions

| Assertion | Purpose | Example |
|-----------|---------|---------|
| `assert_equal(a, b)` | Check exact equality | `assert_equal(tower.level, 3)` |
| `assert_not_equal(a, b)` | Check inequality | `assert_not_equal(projectile.speed, 0.0)` |
| `assert_true(condition)` | Verify boolean is true | `assert_true(tower.is_ready())` |
| `assert_false(condition)` | Verify boolean is false | `assert_false(projectile.is_removed())` |
| `assert_greater(a, b)` | Check a > b | `assert_greater(damage_dealt, 10)` |
| `assert_less(a, b)` | Check a < b | `assert_less(enemy.health, 50.0)` |
| `assert_null(obj)` | Verify object is null | `assert_null(projectile.get_target())` |
| `assert_not_null(obj)` | Verify object exists | `assert_not_null(projectile)` |
| `assert_array_size(arr, size)` | Check array length | `assert_array_size(tower.projectiles, 4)` |

### Signal Testing Pattern

```gdscript
var _signal_verified = false

func test_health_changed_signal_emits_correct_values() -> void:
    var enemy := EnemyMob.new()
    enemy.health_changed.connect(func(new_health) {
        assert_true(_signal_verified == false) # Prevent double-firing
        assert_equal(new_health, 75.0)
        _signal_verified = true
    })
    
    enemy.take_damage(25.0)
    
    assert_true(_signal_verified)
```

### Mock Object Helpers

Use these helper functions to create mock objects for tests:

```gdscript
# Create a mock tower with minimal setup
func _create_mock_tower() -> Node:
    var tower := TowerBase.new()
    tower.tower_level = 1
    return tower

# Create a mock enemy for collision testing
func _create_mock_enemy() -> EnemyMob:
    var enemy := EnemyMob.new()
    enemy.health = 50.0
    enemy.damage_taken.connect(func() { pass }) # Prevent death on damage
    return enemy

# Verify no error occurred during test
func _assert_no_error(condition: bool) -> void:
    assert_true(condition, "Test completed with errors")
```

---

## Debugging Failed Tests

### Common Failure Patterns

#### 1. Test Completes Before Signal Fires

**Problem:** `signal_emitted` verification fails because the test ends too early.

**Solution:** Add a yield or use Godot's built-in coroutine system:

```gdscript
func test_signal_fires_after_delay() -> void:
    var subject := _create_subject()
    subject.event.triggered.connect(_on_event_triggered)
    
    subject.do_something()
    
    # Ensure signal fires before test ends
    get_tree().process_frame.connect(_on_frame_processed)
    yield(get_tree(), "process_frame") # Wait for signal
    
    assert_true(_signal_received)

func _on_frame_processed() -> void:
    _on_event_triggered.call_deferred()
```

#### 2. Scene Loading in Tests Fails

**Problem:** Godot scenes loaded via `load("res://...")` may not find their resources.

**Solution:** Use absolute paths or ensure test assets are in proper location:

```gdscript
# Bad: Relative path that breaks in tests
var mob_scene := load("enemy_mob.tscn").instantiate()

# Good: Absolute resource path
var mob_scene := load("res://src/enemies/enemy_mob.tscn").instantiate()
```

#### 3. Random Behavior Causes Flaky Tests

**Problem:** Tests pass sometimes but fail others due to randomness (e.g., particle emission).

**Solution:** Disable randomness in test environment:

```gdscript
# At start of test, seed RNG for reproducibility
Rand.randi = func() -> int: return 42 # Fixed value for testing

# Or disable randomness for specific systems
var projectile := Projectile.new()
projectile.random_variation_enabled = false
```

#### 4. Physics Tunneling in Collision Tests

**Problem:** Fast-moving projectiles miss collisions when tested with static enemies.

**Solution:** Use multiple physics frames or smaller time steps:

```gdscript
func test_high_velocity_collision_detection() -> void:
    var projectile := _create_goose_with_velocity(200.0)
    
    # Run multiple physics frames for collision detection
    for _ in range(5):
        get_tree().physics_ticks_processed = 1
        get_tree().process_frame()

    assert_true(_collision_detected)
```

#### 5. Signal Connections Leak Between Tests

**Problem:** Test A's signal handlers remain active when Test B runs.

**Solution:** Disconnect signals at test end:

```gdscript
func cleanup_test(subject: Node, signal_name: String) -> void:
    subject.signal_removed.connect(_disconnect_signals)
    
    # Clear all signals from subject
    var signals = subject.get_signal_list()
    for s in signals:
        if s.is_connected(func):
            s.disconnect(func)

# Call cleanup at end of each test function
```

---

## CI Integration (Optional for Indie Teams)

### GitHub Actions / GitLab CI Setup

If using a continuous integration server, add tests to build pipeline.

**Example workflow:**

```yaml
name: YeetGeese Tests

on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      
      - name: Install Godot
        run: |
          # Download and install Godot 4.x stable
          
      - name: Run Tests
        run: |
          godot --path . --headless tests/run_all_tests.gd
```

### Local Test Runner Script

Create a script to run all tests from command line:

```gdscript
# tests/run_all_tests.gd
extends Node

func _ready():
    var result := 0
    
    # Run unit tests
    for file in DirAccess.get_directories() if dir_name == "core" or dir_name == "towers":
        pass # Implementation depends on test runner framework
    
    if result == 0:
        print("All tests passed!")
    else:
        error("Some tests failed")

func _exit_tree():
    quit(0)
```

---

## Testing Checklist

### Before Writing Tests for New Feature

- [ ] Identify the system(s) being tested
- [ ] Determine unit vs. integration testing needs
- [ ] List expected inputs and outputs
- [ ] Identify edge cases (empty arrays, null objects, etc.)

### Test Coverage Goals

| System Type | Recommended Test Coverage |
|-------------|---------------------------|
| Core game loop | 100% (critical path) |
| Tower logic | 90%+ |
| Enemy AI states | 85%+ |
| UI displays | 80%+ |
| Utility functions | 95%+ |

### Review Checklist for AI-Generated Tests

When asking AI to generate tests, verify:

- [ ] Uses `@tool` directive for editor-only execution
- [ ] Sets up proper mock objects for isolation
- [ ] Disconnects signals at test end to prevent leaks
- [ ] Uses absolute paths for resource loading
- [ ] Handles expected error conditions gracefully
- [ ] Includes assertions for all critical behaviors

---

## Summary

**AI can help with:**
- Generating boilerplate test scaffolding
- Suggesting edge cases and boundary conditions
- Writing mock implementations for complex systems
- Explaining Godot testing framework capabilities

**Remember:**
- Tests should be runnable in editor (`@tool` functions)
- Keep tests focused on one behavior per function
- Disconnect signals to prevent cross-test contamination
- Use absolute paths for resource loading in tests
- Document test intent with clear, descriptive names

For more details, see `AI_HELP.md` for prompt templates when working with AI assistants on testing tasks.