Feature Test vs Unit Test: When to Use Which?

Al Shahriar — Thu, 14 Aug 2025 16:34:55 +0000

Testing is not just about finding bugs — it’s about building confidence in your code.
As developers, we often hear “Unit Test” and “Feature Test”.
But what’s the difference, and when should you use each?

Unit Test

Purpose: Test small, isolated pieces of code (functions, classes) without dependencies.
Speed: Super fast – no DB, no API calls.
Best for: Business logic, utility functions, services.

Example:

public function test_discount_calculation()
{
    $service = new DiscountService();
    $result = $service->calculate(1000, 10);
    $this->assertEquals(900, $result);
}

Think of it as testing a single brick, not the whole building.

Feature Test
Purpose: Test an entire feature end-to-end — from request → controller/service → database → response.
Speed: Slower – interacts with DB, queues, or APIs.
Best for: Verifying complete workflows like “User Registration”, “Checkout”, “Password Reset”.

Example:

public function test_user_registration()
{
    $response = $this->postJson('/api/register', [
        'name' => 'John Doe',
        'email' => 'john@example.com',
        'password' => 'Password@123',
        'password_confirmation' => 'Password@123',
    ]);

    $response->assertStatus(201);
    $this->assertDatabaseHas('users', ['email' => 'john@example.com']);
}

Think of it as testing the whole building — from the foundation to the roof.

A Step To Step Guide For Laravel Localization

Al Shahriar — Mon, 01 May 2023 09:18:08 +0000

Hello and welcome to this tutorial on Laravel localization! In this tutorial, we'll be going over how to implement localization in your Laravel project.

Localization is the process of adapting your application to a specific locale or language. This is an important feature to include in your application if you want to reach a wider audience.

Step 1: Install Laravel

composer create-project laravel/laravel:^9.0 localization

Step 2: Create Controller
php artisan make:controller LocalizationController --invokable


public function __invoke($langVal)
    {
       Session::put("locale",$langVal);
       return response()->json(['success'=>'Language change 
       successfully.']);

    }

Step 3: Make a route in web.php

Route::get('/', function () {
    return view('home');
});

Route::get('lang/{langVal}', LocalizationController::class);

Step 4: Make a MiddleWare

php artisan make:middleware Localization

public function handle(Request $request, Closure $next)
    {
        if(Session::has("locale"))
            App::setLocale(Session::get("locale"));
        else
            App::setLocale(config("app.locale"));

        return $next($request);
    }

Add LocalizationMiddleware In Kernal.php

  'web' => [
            \App\Http\Middleware\EncryptCookies::class,
            \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
            \Illuminate\Session\Middleware\StartSession::class,
            // \Illuminate\Session\Middleware\AuthenticateSession::class,
            \Illuminate\View\Middleware\ShareErrorsFromSession::class,
            \App\Http\Middleware\VerifyCsrfToken::class,
            \Illuminate\Routing\Middleware\SubstituteBindings::class,
            \App\Http\Middleware\Localization::class,

        ],

Step 5: Create a json File in lang/en.json & lang/bn.jsonbn for bangla and en for english. Always Use Same Key for both language.

en.json

{

    "Home" : "WellCome To My Laravel Localization BLog",
    "Contact" :"0181285****"


}

bn.json

{

    "Home" : "লারাভেল লোকালাইজেশন ব্লগ এ আপনাকে স্বাগতম",
    "Contact" :"০১৮১২৮৫****"

}

Call Lang file in Blade

  <p>{{ __('Home') }}</p>
  <p>{{ __('Contact') }}</p>

Language Shifting Toogle Button Code

 <div class="form-check form-switch d-flex align-items-center gap-2 languge-content">
        <p class="language-text">English</p>
        <div>
            <input class="form-check-input language-btn ms-0 mt-0 languageChange" id="languageChange"
                type="checkbox" {{ Session::get('locale') == 'bn' ? 'checked' : '' }} />
        </div>
        <p class="language-text">বাংলা</p>
    </div>

Get Value from Toogle Button and Pass Value to Change Language

  <script>
    $('.languageChange').click(function() {
        var mode = $(this).prop('checked');
        if (mode == true) {
            var langVal = 'bn';
        } else {
            var langVal = 'en';
        }

        $.ajax({
            type: 'GET',
            url: '/lang/' + langVal,
            success: function(data) {
                location.reload();
                console.log(langVal);

            },
            error: function(data) {
                console.log('Something went wrong.');
            }
        });
    });
</script>

Here Is full Code
Step 6 : Create a blade file home.blade.php

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>Localization Practice</title>
  <style>
    /* Define styles for the header and toggle button */
    header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      background-color: #333;
      color: #fff;
      padding: 10px;
    }

    #toggle {
      background-color: #fff;
      color: #333;
      border: none;
      padding: 5px 10px;
      cursor: pointer;
    }
  </style>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/selectize.js/0.12.6/js/standalone/selectize.min.js"
    integrity="sha256-+C0A5Ilqmu4QcSPxrlGpaZxJ04VjsRjKu+G82kl5UJk=" crossorigin="anonymous"></script>
    <link rel="stylesheet"
    href="https://cdnjs.cloudflare.com/ajax/libs/selectize.js/0.12.6/css/selectize.bootstrap3.min.css"
    integrity="sha256-ze/OEYGcFbPRmvCnrSeKbRTtjG4vGLHXgOqsyLFTRjg=" crossorigin="anonymous" />
<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha1/dist/css/bootstrap.min.css" rel="stylesheet" />

</head>
<body>
  <header>
    <h1>Localization Practice</h1>
    <div class="form-check form-switch d-flex align-items-center gap-2 languge-content">
        <p class="language-text">English</p>
        <div>
            <input class="form-check-input language-btn ms-0 mt-0 languageChange" id="languageChange"
                type="checkbox" {{ Session::get('locale') == 'bn' ? 'checked' : '' }} />
        </div>
        <p class="language-text">বাংলা</p>
    </div>  </header>

  <main>
    <p>{{ __('Home') }}</p>
    <p>{{ __('Contact') }}</p>


  </main>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.4/jquery.min.js"></script>
  <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha1/dist/js/bootstrap.bundle.min.js"></script>

  <script>
    $('.languageChange').click(function() {
        var mode = $(this).prop('checked');
        if (mode == true) {
            var langVal = 'bn';
        } else {
            var langVal = 'en';
        }

        $.ajax({
            type: 'GET',
            url: '/lang/' + langVal,
            success: function(data) {
                location.reload();
                console.log(langVal);

            },
            error: function(data) {
                console.log('Something went wrong.');
            }
        });
    });
</script>
</body>
</html>

Here is The Visual

DEV Community: Al Shahriar

Feature Test vs Unit Test: When to Use Which?

A Step To Step Guide For Laravel Localization