diff --git a/src/Helpers/Projects/ProjectBuildRequest.php b/src/Helpers/Projects/ProjectBuildRequest.php
index 3ae4db10..093581f4 100644
--- a/src/Helpers/Projects/ProjectBuildRequest.php
+++ b/src/Helpers/Projects/ProjectBuildRequest.php
@@ -50,6 +50,10 @@ final class ProjectBuildRequest
      */
     public function __construct(Project $project, int $number_of_builds)
     {
+        if ($number_of_builds < 1) {
+            throw new \InvalidArgumentException('Number of builds must be at least 1!');
+        }
+
         $this->project = $project;
         $this->number_of_builds = $number_of_builds;
 
diff --git a/tests/Helpers/Projects/ProjectBuildRequestTest.php b/tests/Helpers/Projects/ProjectBuildRequestTest.php
new file mode 100644
index 00000000..0af0aa72
--- /dev/null
+++ b/tests/Helpers/Projects/ProjectBuildRequestTest.php
@@ -0,0 +1,177 @@
+<?php
+/*
+ * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
+ *
+ *  Copyright (C) 2019 - 2023 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 Affero General Public License as published
+ *  by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+namespace App\Tests\Helpers\Projects;
+
+use App\Entity\Parts\MeasurementUnit;
+use App\Entity\Parts\Part;
+use App\Entity\Parts\PartLot;
+use App\Entity\ProjectSystem\Project;
+use App\Entity\ProjectSystem\ProjectBOMEntry;
+use App\Helpers\Projects\ProjectBuildRequest;
+use PHPUnit\Framework\TestCase;
+
+class ProjectBuildRequestTest extends TestCase
+{
+
+    /** @var MeasurementUnit $float_unit */
+    private MeasurementUnit $float_unit;
+
+    /** @var Project */
+    private $project1;
+    /** @var ProjectBOMEntry */
+    private $bom_entry1a;
+    /** @var ProjectBOMEntry */
+    private $bom_entry1b;
+    /** @var ProjectBOMEntry */
+    private $bom_entry1c;
+
+    /** @var PartLot $lot1a */
+    private $lot1a;
+    /** @var PartLot $lot1b */
+    private $lot1b;
+    private $lot2;
+
+    /** @var Part */
+    private $part1;
+    /** @var Part */
+    private $part2;
+
+
+    public function setUp(): void
+    {
+        $this->float_unit = new MeasurementUnit();
+        $this->float_unit->setName('float');
+        $this->float_unit->setUnit('f');
+        $this->float_unit->setIsInteger(false);
+        $this->float_unit->setUseSIPrefix(true);
+
+        //Setup some example parts and part lots
+        $this->part1 = new Part();
+        $this->part1->setName('Part 1');
+        $this->lot1a = new class extends PartLot {
+            public function getID(): ?int
+            {
+                return 1;
+            }
+        };
+        $this->part1->addPartLot($this->lot1a);
+        $this->lot1a->setAmount(10);
+        $this->lot1a->setDescription('Lot 1a');
+
+        $this->lot1b = new class extends PartLot {
+            public function getID(): ?int
+            {
+                return 2;
+            }
+        };
+        $this->part1->addPartLot($this->lot1b);
+        $this->lot1b->setAmount(20);
+        $this->lot1b->setDescription('Lot 1b');
+
+        $this->part2 = new Part();
+
+        $this->part2->setName('Part 2');
+        $this->part2->setPartUnit($this->float_unit);
+        $this->lot2 = new PartLot();
+        $this->part2->addPartLot($this->lot2);
+        $this->lot2->setAmount(2.5);
+        $this->lot2->setDescription('Lot 2');
+
+        $this->bom_entry1a = new ProjectBOMEntry();
+        $this->bom_entry1a->setPart($this->part1);
+        $this->bom_entry1a->setQuantity(2);
+
+        $this->bom_entry1b = new ProjectBOMEntry();
+        $this->bom_entry1b->setPart($this->part2);
+        $this->bom_entry1b->setQuantity(1.5);
+
+        $this->bom_entry1c = new ProjectBOMEntry();
+        $this->bom_entry1c->setName('Non-part BOM entry');
+        $this->bom_entry1c->setQuantity(4);
+
+
+        $this->project1 = new Project();
+        $this->project1->setName('Project 1');
+        $this->project1->addBomEntry($this->bom_entry1a);
+        $this->project1->addBomEntry($this->bom_entry1b);
+        $this->project1->addBomEntry($this->bom_entry1c);
+    }
+
+    public function testInitialization()
+    {
+        //The values should be already prefilled correctly
+        $request = new ProjectBuildRequest($this->project1, 10);
+        //We need totally 20: Take 10 from the first (maximum 10) and 10 from the second (maximum 20)
+        $this->assertEquals(10, $request->getLotWithdrawAmount($this->lot1a));
+        $this->assertEquals(10, $request->getLotWithdrawAmount($this->lot1b));
+
+        //If the needed amount is higher than the maximum, we should get the maximum
+        $this->assertEquals(2.5, $request->getLotWithdrawAmount($this->lot2));
+    }
+
+    public function testGetNumberOfBuilds()
+    {
+        $build_request = new ProjectBuildRequest($this->project1, 5);
+        $this->assertEquals(5, $build_request->getNumberOfBuilds());
+    }
+
+    public function testGetProject()
+    {
+        $build_request = new ProjectBuildRequest($this->project1, 5);
+        $this->assertEquals($this->project1, $build_request->getProject());
+    }
+
+    public function testGetNeededAmountForBOMEntry()
+    {
+        $build_request = new ProjectBuildRequest($this->project1, 5);
+        $this->assertEquals(10, $build_request->getNeededAmountForBOMEntry($this->bom_entry1a));
+        $this->assertEquals(7.5, $build_request->getNeededAmountForBOMEntry($this->bom_entry1b));
+        $this->assertEquals(20, $build_request->getNeededAmountForBOMEntry($this->bom_entry1c));
+    }
+
+    public function testGetSetLotWithdrawAmount()
+    {
+        $build_request = new ProjectBuildRequest($this->project1, 5);
+
+        //We can set the amount for a lot either via the lot object or via the ID
+        $build_request->setLotWithdrawAmount($this->lot1a, 2);
+        $build_request->setLotWithdrawAmount($this->lot1b->getID(), 3);
+
+        //And it should be possible to get the amount via the lot object or via the ID
+        $this->assertEquals(2, $build_request->getLotWithdrawAmount($this->lot1a->getID()));
+        $this->assertEquals(3, $build_request->getLotWithdrawAmount($this->lot1b));
+    }
+
+    public function testGetWithdrawAmountSum()
+    {
+        //The sum of all withdraw amounts for an BOM entry (over all lots of the associated part) should be correct
+        $build_request = new ProjectBuildRequest($this->project1, 5);
+
+        $build_request->setLotWithdrawAmount($this->lot1a, 2);
+        $build_request->setLotWithdrawAmount($this->lot1b, 3);
+
+        $this->assertEquals(5, $build_request->getWithdrawAmountSum($this->bom_entry1a));
+        $build_request->setLotWithdrawAmount($this->lot2, 1.5);
+        $this->assertEquals(1.5, $build_request->getWithdrawAmountSum($this->bom_entry1b));
+    }
+
+
+}