feat: add MultiDriver

tests/Unit/Drivers/MultiDriverTest.php

@@ -0,0 +1,80 @@
+<?php
+
+declare(strict_types=1);
+
+use Wearepixel\Cart\Drivers\MultiDriver;
+use Wearepixel\Cart\Drivers\NullDriver;
+
+describe('MultiDriver', function () {
+    beforeEach(function () {
+        $this->primary = new NullDriver('test-session');
+        $this->secondary = new NullDriver('test-session');
+        $this->driver = new MultiDriver([$this->primary, $this->secondary]);
+    });
+
+    test('returns session key from primary driver', function () {
+        expect($this->driver->getSessionKey())->toBe('test-session');
+    });
+
+    test('returns multi as driver name', function () {
+        expect($this->driver->getDriverName())->toBe('multi');
+    });
+
+    test('reads items from primary driver', function () {
+        $this->primary->putItems([['id' => 1]]);
+        $this->secondary->putItems([['id' => 2]]);
+
+        expect($this->driver->getItems())->toBe([['id' => 1]]);
+    });
+
+    test('writes items to all drivers', function () {
+        $this->driver->putItems([['id' => 1]]);
+
+        expect($this->primary->getItems())->toBe([['id' => 1]]);
+        expect($this->secondary->getItems())->toBe([['id' => 1]]);
+    });
+
+    test('reads conditions from primary driver', function () {
+        $this->primary->putConditions([['name' => 'GST']]);
+        $this->secondary->putConditions([['name' => 'Other']]);
+
+        expect($this->driver->getConditions())->toBe([['name' => 'GST']]);
+    });
+
+    test('writes conditions to all drivers', function () {
+        $this->driver->putConditions([['name' => 'GST']]);
+
+        expect($this->primary->getConditions())->toBe([['name' => 'GST']]);
+        expect($this->secondary->getConditions())->toBe([['name' => 'GST']]);
+    });
+
+    test('clearItems clears items on all drivers', function () {
+        $this->driver->putItems([['id' => 1]]);
+        $this->driver->clearItems();
+
+        expect($this->primary->getItems())->toBe([]);
+        expect($this->secondary->getItems())->toBe([]);
+    });
+
+    test('flush flushes all drivers', function () {
+        $this->driver->putItems([['id' => 1]]);
+        $this->driver->putConditions([['name' => 'GST']]);
+        $this->driver->flush();
+
+        expect($this->primary->getItems())->toBe([]);
+        expect($this->primary->getConditions())->toBe([]);
+        expect($this->secondary->getItems())->toBe([]);
+        expect($this->secondary->getConditions())->toBe([]);
+    });
+
+    test('setSessionKey updates all drivers', function () {
+        $this->driver->setSessionKey('new-key');
+
+        expect($this->primary->getSessionKey())->toBe('new-key');
+        expect($this->secondary->getSessionKey())->toBe('new-key');
+    });
+
+    test('throws when constructed with no drivers', function () {
+        expect(fn() => new MultiDriver([]))->toThrow(InvalidArgumentException::class);
+    });
+});