Fixed an exception in getmaxDiscountAmount().

This should fixes an 500 error code, that showed up on some pages. Also added a test method to test this function.

src/Services/PricedetailHelper.php

@@ -25,6 +25,8 @@ namespace App\Services;
 use App\Entity\Parts\Part;
 use App\Entity\PriceInformations\Currency;
 use App\Entity\PriceInformations\Pricedetail;
+use Doctrine\Common\Collections\ArrayCollection;
+use Doctrine\ORM\PersistentCollection;
 use Locale;
 
 class PricedetailHelper
@@ -53,20 +55,32 @@ class PricedetailHelper
         foreach ($orderdetails as $orderdetail) {
             $pricedetails = $orderdetail->getPricedetails();
             //The orderdetail must have pricedetails, otherwise this will not work!
-            if (empty($pricedetails)) {
+            if (count($pricedetails) === 0) {
                 continue;
             }
 
+            if ($pricedetails instanceof PersistentCollection) {
                 /* Pricedetails in orderdetails are ordered by min discount quantity,
                     so our first object is our min order amount for the current orderdetail */
                 $max_amount = $pricedetails->last()->getMinDiscountQuantity();
+            } else {
+                // We have to sort the pricedetails manually
+                $array = $pricedetails->map(
+                    function (Pricedetail $pricedetail) {
+                        return $pricedetail->getMinDiscountQuantity();
+                    }
+                )->toArray();
+                sort($array);
+                $max_amount = end($array);
+            }
+
 
             if ($max_amount > $max) {
                 $max = $max_amount;
             }
         }
 
-        if ($max > 0) {
+        if ($max > 0.0) {
             return $max;
         }
 

tests/Services/PricedetailHelperTest.php

@@ -0,0 +1,93 @@
+<?php
+/**
+ * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony)
+ *
+ * Copyright (C) 2019 Jan Böhmer (https://github.com/jbtronics)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ *
+ */
+
+namespace App\Tests\Services;
+
+
+use App\Entity\Parts\Part;
+use App\Entity\PriceInformations\Orderdetail;
+use App\Entity\PriceInformations\Pricedetail;
+use App\Services\AmountFormatter;
+use App\Services\PricedetailHelper;
+use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
+
+class PricedetailHelperTest extends WebTestCase
+{
+    /**
+     * @var AmountFormatter
+     */
+    protected $service;
+
+    public function setUp()
+    {
+        parent::setUp();
+        //Get an service instance.
+        self::bootKernel();
+        $this->service = self::$container->get(PricedetailHelper::class);
+    }
+
+    public function maxDiscountAmountDataProvider()
+    {
+        $part = new Part();
+        yield [$part, null, 'Part without any orderdetails failed!'];
+
+        //Part with empty orderdetails
+        $part = new Part();
+        $orderdetail = new Orderdetail();
+        $part->addOrderdetail($orderdetail);
+        yield [$part, null, 'Part with one empty orderdetail failed!'];
+
+        $part = new Part();
+        $orderdetail = new Orderdetail();
+        $part->addOrderdetail($orderdetail);
+        $orderdetail->addPricedetail((new Pricedetail())->setMinDiscountQuantity(1));
+        yield [$part, 1.0, 'Part with one pricedetail failed!'];
+
+        $part = new Part();
+        $orderdetail = new Orderdetail();
+        $part->addOrderdetail($orderdetail);
+        $orderdetail->addPricedetail((new Pricedetail())->setMinDiscountQuantity(1));
+        $orderdetail->addPricedetail((new Pricedetail())->setMinDiscountQuantity(2));
+        $orderdetail->addPricedetail((new Pricedetail())->setMinDiscountQuantity(1.5));
+        yield [$part, 2.0, 'Part with multiple pricedetails failed!'];
+
+        $part = new Part();
+        $orderdetail = new Orderdetail();
+        $orderdetail2 = new Orderdetail();
+        $part->addOrderdetail($orderdetail);
+        $part->addOrderdetail($orderdetail2);
+        $orderdetail->addPricedetail((new Pricedetail())->setMinDiscountQuantity(1));
+        $orderdetail->addPricedetail((new Pricedetail())->setMinDiscountQuantity(2));
+        $orderdetail->addPricedetail((new Pricedetail())->setMinDiscountQuantity(1.5));
+        $orderdetail2->addPricedetail((new Pricedetail())->setMinDiscountQuantity(10));
+
+        yield [$part, 10.0, 'Part with multiple orderdetails failed'];
+    }
+
+    /**
+     * @dataProvider maxDiscountAmountDataProvider
+     */
+    public function testGetMaxDiscountAmount(Part $part, ?float $expected_result, string $message)
+    {
+        $this->assertEquals($expected_result, $this->service->getMaxDiscountAmount($part), $message);
+    }
+}