Test-Driven Development for Laravel

Test-Driven Development for Laravel

Overview

Write the test first. Watch it fail. Write minimal code to pass.

This skill adapts TDD principles specifically for Laravel applications using Pest PHP, Laravel's testing features, and framework-specific patterns.

When to Use

Always for Laravel:

• New features (controllers, models, services)
• Bug fixes
• API endpoints
• Database migrations and models
• Form validation
• Authorization policies
• Queue jobs
• Artisan commands
• Middleware

Exceptions (ask your human partner):

• Throwaway prototypes
• Configuration files
• View-only changes (no logic)

The Laravel TDD Cycle

RED → Verify RED → GREEN → Verify GREEN → REFACTOR → Repeat

RED - Write Failing Test

Write one minimal test showing what the Laravel feature should do.

Feature Test Example:

<?php

use App\Models\User;
use App\Models\Post;

test('authenticated user can create post', function () {
    $user = User::factory()->create();
    
    $this->actingAs($user)
        ->post('/​posts', [
            'title' => 'My First Post',
            'content' => 'Post content here',
        ])
        ->assertRedirect('/​posts');
    
    expect(Post::where('title', 'My First Post')->exists())->toBeTrue();
    expect(Post::first()->user_id)->toBe($user->id);
});

Verify RED - Watch It Fail

php artisan test --filter=authenticated_user_can_create_post

GREEN - Minimal Laravel Code

Write simplest Laravel code to pass the test.

Verify GREEN - Watch It Pass

php artisan test

REFACTOR - Clean Up Laravel Code

After green only:

• Extract services for complex logic
• Create policies for authorization
• Add query scopes for reusability
• Use events for side effects

Laravel-Specific Test Patterns

Database Testing

use Illuminate\Foundation\Testing\RefreshDatabase;

uses(RefreshDatabase::class);

test('creates post in database', function () {
    $user = User::factory()->create();
    
    $this->actingAs($user)
        ->post('/​posts', ['title' => 'Test', 'content' => 'Content']);
    
    $this->assertDatabaseHas('posts', ['title' => 'Test']);
});

Authorization Testing

test('user cannot delete others posts', function () {
    $user = User::factory()->create();
    $post = Post::factory()->create();
    
    $this->actingAs($user)
        ->delete("/​posts/​{$post->id}")
        ->assertForbidden();
});

API Testing

test('creates post via API', function () {
    $user = User::factory()->create();
    
    $this->actingAs($user, 'sanctum')
        ->postJson('/​api/​posts', ['title' => 'API Post', 'content' => 'Content'])
        ->assertCreated();
});

Verification Checklist

• Migration test passes
• Model relationships tested
• Controller actions tested
• Validation rules tested
• Authorization tested
• Database state verified
• All tests passing
• Used RefreshDatabase
• Used factories

Remember

Every Laravel feature → Test exists and failed first
Otherwise → Not TDD