adding a cart

tests/Feature/Http/Controllers/CartControllerTest.php

@@ -0,0 +1,77 @@
+<?php
+
+use App\Models\Cart;
+use App\Models\Product;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+
+uses(RefreshDatabase::class);
+
+test('guests can add to cart without being authenticated', function () {
+    $product = Product::factory()->create();
+
+    $this->postJson('/api/cart', ['product_id' => $product->id])
+        ->assertSuccessful()
+        ->assertJsonFragment(['product_id' => $product->id, 'quantity' => 1]);
+});
+
+test('adding a product creates a cart and returns cart items', function () {
+    $product = Product::factory()->create();
+
+    $response = $this->postJson('/api/cart', ['product_id' => $product->id]);
+
+    $response->assertSuccessful()
+        ->assertJsonFragment(['product_id' => $product->id, 'quantity' => 1]);
+
+    expect(Cart::count())->toBe(1);
+});
+
+test('adding the same product increments quantity', function () {
+    $product = Product::factory()->create();
+
+    $this->postJson('/api/cart', ['product_id' => $product->id]);
+    $response = $this->postJson('/api/cart', ['product_id' => $product->id]);
+
+    $response->assertSuccessful()
+        ->assertJsonFragment(['product_id' => $product->id, 'quantity' => 2]);
+});
+
+test('adding a non-existent product fails validation', function () {
+    $this->postJson('/api/cart', ['product_id' => 9999])
+        ->assertUnprocessable();
+});
+
+test('updating a cart item changes its quantity', function () {
+    $product = Product::factory()->create();
+    $cart = Cart::factory()->create(['user_id' => null]);
+    $cart->products()->attach($product->id, ['quantity' => 1]);
+
+    $response = $this->withSession(['cart_id' => $cart->id])
+        ->patchJson("/api/cart/{$product->id}", ['quantity' => 5]);
+
+    $response->assertSuccessful()
+        ->assertJsonFragment(['product_id' => $product->id, 'quantity' => 5]);
+});
+
+test('removing a product detaches it from the cart', function () {
+    $product = Product::factory()->create();
+    $cart = Cart::factory()->create(['user_id' => null]);
+    $cart->products()->attach($product->id, ['quantity' => 2]);
+
+    $response = $this->withSession(['cart_id' => $cart->id])
+        ->deleteJson("/api/cart/{$product->id}");
+
+    $response->assertSuccessful()
+        ->assertJsonMissing(['product_id' => $product->id]);
+
+    expect($cart->fresh()->products)->toHaveCount(0);
+});
+
+test('a cart can optionally belong to a user', function () {
+    $user = User::factory()->create();
+    $cartWithUser = Cart::factory()->create(['user_id' => $user->id]);
+    $cartGuest = Cart::factory()->create(['user_id' => null]);
+
+    expect($cartWithUser->user)->toBeInstanceOf(User::class);
+    expect($cartGuest->user)->toBeNull();
+});