To achieve high test coverage for Laravel applications, the key is to write meaningful tests to verify core logic, boundary situations, and integration points. 1. Use functional tests to simulate real user interactions and cover request/response cycles, controllers, middleware, routing and database operations; 2. Write unit tests for complex business logic, service classes or tools, and use appropriate mocks to isolate the tested classes; 3. Use model factories and seeders to generate consistent test data, and keep the test efficient through RefreshDatabase; 4. Use PHPUnit or Pest for coverage, focusing on important paths rather than simply pursuing row count coverage. Balance different test types, focus on actual functions and dependency logic, and gradually improve test coverage.

Achieving high test coverage in a Laravel application isn't just about hitting a percentage — it's about ensuring your core logic, edge cases, and integration points are solid. The key is to write meaningful tests that actually validate behavior, not just code lines.

Here's how to go about it effectively:

1. Use Feature Tests for Real-World Scenarios

Feature tests (HTTP tests) simulate real user interactions. They're great for testing full request/response cycles and cover controllers, middleware, routes, and even database interactions.

What to do:

• Write tests that mimic actual API or UI usage.
• Cover common success paths and error scenarios.
• Test authentication flows, form validation, redirects, and JSON responses.

For example:

 public function test_user_can_register()
{
    $response = $this->post('/register', [
        'name' => 'Test User',
        'email' => 'test@example.com',
        'password' => 'password',
    ]);

    $response->assertRedirect('/home');
    $this->assertDatabaseHas('users', ['email' => 'test@example.com']);
}

These kinds of tests often give better coverage than unit tests because they touch multiple layers of your app.

2. Write Unit Tests for Core Logic

Unit tests focus on individual classes or methods. These are ideal for complex business logic, services, or utilities that don't rely on the framework's HTTP layer.

Where to apply them:

• Custom service classes
• Formatters, calculators, validators
• Repository methods

Use mocks where appropriate to isolate the class under test.

Example:

 public function test_discount_calculator_applies_10_percent()
{
    $calculator = new DiscountCalculator();
    $total = $calculator->applyDiscount(100, 10);

    $this->assertEquals(90, $total);
}

Don't overdo it with mocking though — keep it realistic and focused.

3. Don't Forget About Database and Seeders

Your models and database structure should be tested too. Factory and seeders can help you generate consistent test data.

Tips:

• Use Laravel model factories to create test data quickly.
• Make sure to assert against the database after actions like creating, updating, or deleting records.
• Use RefreshDatabase to keep tests fast and clean.

Also, if you're using migrations and seeders, write tests that verify seen data is correctly applied, especially if other parts of your app depends on it.

4. Use Pest or PHPUnit with Coverage Reporting

Laravel defaults to PHPUnit, but Pest offers a more expressive syntax and integrates well.

To check coverage:

 php artisan test --coverage

This will show which lines are executed during your tests. Aim to cover:

• All controller methods
• Any non-trivial model scopes or mutators
• Jobs, listeners, and commands

But remember: 100% line coverage doesn't mean 100% correctness . Focus on covering important paths and edge cases.

Final Thoughts

High test coverage in Laravel comes from balancing different types of tests and focusing on what really matters — functionality users interact with or depends on behind the scenes. You don't need to test every getter or simple accessor, but anything with logic or integration should have coverage.

Start small, add tests as you build features, and use coverage tools to guide improvements. It's not magic, just steady, thoughtful work.

Basically that's it.

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