From db35a97910523458f9cfe4eb644be0224a1d9d8b Mon Sep 17 00:00:00 2001
From: Yisroel Baum <yisroel.d.baum@gmail.com>
Date: Sun, 24 May 2026 22:28:44 +0300
Subject: [PATCH] test set elements

---
 backend/tests/Fakes/FakeElementRepository.php |  68 +++++++
 backend/tests/Fakes/FakeSetRepository.php     |  57 ++++++
 backend/tests/Unit/Element/ElementTest.php    |  33 ++++
 .../Element/UseCases/CreateElementTest.php    | 171 ++++++++++++++++++
 backend/tests/Unit/Set/SetTest.php            |  17 ++
 .../tests/Unit/Set/UseCases/CreateSetTest.php |  63 +++++++
 6 files changed, 409 insertions(+)
 create mode 100644 backend/tests/Fakes/FakeElementRepository.php
 create mode 100644 backend/tests/Fakes/FakeSetRepository.php
 create mode 100644 backend/tests/Unit/Element/ElementTest.php
 create mode 100644 backend/tests/Unit/Element/UseCases/CreateElementTest.php
 create mode 100644 backend/tests/Unit/Set/SetTest.php
 create mode 100644 backend/tests/Unit/Set/UseCases/CreateSetTest.php

diff --git a/backend/tests/Fakes/FakeElementRepository.php b/backend/tests/Fakes/FakeElementRepository.php
new file mode 100644
index 0000000..d624a9a
--- /dev/null
+++ b/backend/tests/Fakes/FakeElementRepository.php
@@ -0,0 +1,68 @@
+<?php
+
+namespace Tests\Fakes;
+
+use App\Element\CreateElementDto;
+use App\Element\Element;
+use App\Element\ElementRepository;
+
+class FakeElementRepository implements ElementRepository
+{
+    /**
+     * @var Element[]
+     */
+    private array $elementsById = [];
+
+    public function create(CreateElementDto $dto): Element
+    {
+        $id = count($this->elementsById) + 1;
+        $element = new Element(
+            id: $id,
+            title: $dto->title,
+            set: $dto->set,
+            parentElement: $dto->parentElement,
+        );
+        $this->elementsById[$id] = $element;
+
+        return $element;
+    }
+
+    public function find(int $id): ?Element
+    {
+        if (! isset($this->elementsById[$id])) {
+            return null;
+        }
+
+        return $this->cloneElement($this->elementsById[$id]);
+    }
+
+    /**
+     * @return Element[]
+     */
+    public function findBySetId(int $id): array
+    {
+        $elements = [];
+        foreach ($this->elementsById as $element) {
+            if ($element->getSet()->getId() === $id) {
+                $elements[] = $this->cloneElement($element);
+            }
+        }
+
+        return $elements;
+    }
+
+    private function cloneElement(Element $element): Element
+    {
+        $parentElement = $element->getParentElement();
+        if ($parentElement !== null) {
+            $parentElement = $this->cloneElement($parentElement);
+        }
+
+        return new Element(
+            id: $element->getId(),
+            title: $element->getTitle(),
+            set: $element->getSet(),
+            parentElement: $parentElement,
+        );
+    }
+}
diff --git a/backend/tests/Fakes/FakeSetRepository.php b/backend/tests/Fakes/FakeSetRepository.php
new file mode 100644
index 0000000..295e619
--- /dev/null
+++ b/backend/tests/Fakes/FakeSetRepository.php
@@ -0,0 +1,57 @@
+<?php
+
+namespace Tests\Fakes;
+
+use App\Set\CreateSetDto;
+use App\Set\Set as DomainSet;
+use App\Set\SetRepository;
+
+class FakeSetRepository implements SetRepository
+{
+    /**
+     * @var DomainSet[]
+     */
+    private array $setsById = [];
+
+    public function create(CreateSetDto $dto): DomainSet
+    {
+        $id = count($this->setsById) + 1;
+        $set = new DomainSet(
+            id: $id,
+            name: $dto->name,
+        );
+        $this->setsById[$id] = $set;
+
+        return $set;
+    }
+
+    public function find(int $id): ?DomainSet
+    {
+        if (! isset($this->setsById[$id])) {
+            return null;
+        }
+
+        return $this->cloneSet($this->setsById[$id]);
+    }
+
+    /**
+     * @return DomainSet[]
+     */
+    public function getAll(): array
+    {
+        $sets = [];
+        foreach ($this->setsById as $set) {
+            $sets[] = $this->cloneSet($set);
+        }
+
+        return $sets;
+    }
+
+    private function cloneSet(DomainSet $set): DomainSet
+    {
+        return new DomainSet(
+            id: $set->getId(),
+            name: $set->getName(),
+        );
+    }
+}
diff --git a/backend/tests/Unit/Element/ElementTest.php b/backend/tests/Unit/Element/ElementTest.php
new file mode 100644
index 0000000..3e914d9
--- /dev/null
+++ b/backend/tests/Unit/Element/ElementTest.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace Tests\Unit\Element;
+
+use App\Element\Element;
+use App\Set\Set as DomainSet;
+use Tests\TestCase;
+
+class ElementTest extends TestCase
+{
+    public function testCreatesElementWithNullableParent(): void
+    {
+        $set = new DomainSet(1, 'Daily learning');
+        $rootElement = new Element(
+            id: 1,
+            title: 'Root',
+            set: $set,
+            parentElement: null,
+        );
+        $childElement = new Element(
+            id: 2,
+            title: 'Child',
+            set: $set,
+            parentElement: $rootElement,
+        );
+
+        $this->assertSame(2, $childElement->getId());
+        $this->assertSame('Child', $childElement->getTitle());
+        $this->assertSame($set, $childElement->getSet());
+        $this->assertSame($rootElement, $childElement->getParentElement());
+        $this->assertNull($rootElement->getParentElement());
+    }
+}
diff --git a/backend/tests/Unit/Element/UseCases/CreateElementTest.php b/backend/tests/Unit/Element/UseCases/CreateElementTest.php
new file mode 100644
index 0000000..da6f024
--- /dev/null
+++ b/backend/tests/Unit/Element/UseCases/CreateElementTest.php
@@ -0,0 +1,171 @@
+<?php
+
+namespace Tests\Unit\Element\UseCases;
+
+use App\Element\Element;
+use App\Element\UseCases\CreateElement\CreateElement;
+use App\Element\UseCases\CreateElement\CreateElementRequest;
+use App\Exceptions\BadRequestException;
+use App\Set\CreateSetDto;
+use DomainException;
+use Tests\Fakes\FakeElementRepository;
+use Tests\Fakes\FakeSetRepository;
+use Tests\TestCase;
+
+class CreateElementTest extends TestCase
+{
+    private FakeSetRepository $setRepo;
+
+    private FakeElementRepository $elementRepo;
+
+    private CreateElement $createElement;
+
+    protected function setUp(): void
+    {
+        $this->setRepo = new FakeSetRepository();
+        $this->elementRepo = new FakeElementRepository();
+        $this->createElement = new CreateElement(
+            $this->elementRepo,
+            $this->setRepo,
+        );
+    }
+
+    public function testCreatesRootElement(): void
+    {
+        $set = $this->setRepo->create(new CreateSetDto('Daily learning'));
+
+        $element = $this->createElement->execute(new CreateElementRequest(
+            setId: $set->getId(),
+            title: 'Root',
+            parentElementId: null,
+        ));
+
+        $this->assertInstanceOf(Element::class, $element);
+        $this->assertSame('Root', $element->getTitle());
+        $this->assertSame($set->getId(), $element->getSet()->getId());
+        $this->assertNull($element->getParentElement());
+    }
+
+    public function testCreatesChildElement(): void
+    {
+        $set = $this->setRepo->create(new CreateSetDto('Daily learning'));
+        $rootElement = $this->createElement->execute(
+            new CreateElementRequest(
+                setId: $set->getId(),
+                title: 'Root',
+                parentElementId: null,
+            )
+        );
+
+        $childElement = $this->createElement->execute(
+            new CreateElementRequest(
+                setId: $set->getId(),
+                title: 'Child',
+                parentElementId: $rootElement->getId(),
+            )
+        );
+
+        $this->assertSame('Child', $childElement->getTitle());
+        $this->assertSame(
+            $rootElement->getId(),
+            $childElement->getParentElement()->getId(),
+        );
+    }
+
+    public function testThrowsWhenSetIdMissing(): void
+    {
+        $this->expectException(BadRequestException::class);
+        $this->expectExceptionMessage('setId is required');
+
+        $this->createElement->execute(new CreateElementRequest(
+            setId: null,
+            title: 'Root',
+            parentElementId: null,
+        ));
+    }
+
+    public function testThrowsWhenTitleMissing(): void
+    {
+        $this->expectException(BadRequestException::class);
+        $this->expectExceptionMessage('title is required');
+
+        $this->createElement->execute(new CreateElementRequest(
+            setId: 1,
+            title: null,
+            parentElementId: null,
+        ));
+    }
+
+    public function testThrowsWhenSetDoesNotExist(): void
+    {
+        $this->expectException(DomainException::class);
+        $this->expectExceptionMessage('Set with id: 99 doesnt exist');
+
+        $this->createElement->execute(new CreateElementRequest(
+            setId: 99,
+            title: 'Root',
+            parentElementId: null,
+        ));
+    }
+
+    public function testThrowsWhenParentElementDoesNotExist(): void
+    {
+        $set = $this->setRepo->create(new CreateSetDto('Daily learning'));
+
+        $this->expectException(DomainException::class);
+        $this->expectExceptionMessage(
+            'Element with id: 99 doesnt exist'
+        );
+
+        $this->createElement->execute(new CreateElementRequest(
+            setId: $set->getId(),
+            title: 'Child',
+            parentElementId: 99,
+        ));
+    }
+
+    public function testThrowsWhenRootElementAlreadyExists(): void
+    {
+        $set = $this->setRepo->create(new CreateSetDto('Daily learning'));
+        $this->createElement->execute(new CreateElementRequest(
+            setId: $set->getId(),
+            title: 'Root',
+            parentElementId: null,
+        ));
+
+        $this->expectException(DomainException::class);
+        $this->expectExceptionMessage(
+            'A root element already exists for this set'
+        );
+
+        $this->createElement->execute(new CreateElementRequest(
+            setId: $set->getId(),
+            title: 'Another root',
+            parentElementId: null,
+        ));
+    }
+
+    public function testThrowsWhenParentBelongsToAnotherSet(): void
+    {
+        $parentSet = $this->setRepo->create(new CreateSetDto('Parent set'));
+        $childSet = $this->setRepo->create(new CreateSetDto('Child set'));
+        $parentElement = $this->createElement->execute(
+            new CreateElementRequest(
+                setId: $parentSet->getId(),
+                title: 'Parent root',
+                parentElementId: null,
+            )
+        );
+
+        $this->expectException(DomainException::class);
+        $this->expectExceptionMessage(
+            'Parent element must belong to the same set'
+        );
+
+        $this->createElement->execute(new CreateElementRequest(
+            setId: $childSet->getId(),
+            title: 'Invalid child',
+            parentElementId: $parentElement->getId(),
+        ));
+    }
+}
diff --git a/backend/tests/Unit/Set/SetTest.php b/backend/tests/Unit/Set/SetTest.php
new file mode 100644
index 0000000..a98ac5f
--- /dev/null
+++ b/backend/tests/Unit/Set/SetTest.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace Tests\Unit\Set;
+
+use App\Set\Set as DomainSet;
+use Tests\TestCase;
+
+class SetTest extends TestCase
+{
+    public function testCreatesSetWithName(): void
+    {
+        $set = new DomainSet(1, 'Daily learning');
+
+        $this->assertSame(1, $set->getId());
+        $this->assertSame('Daily learning', $set->getName());
+    }
+}
diff --git a/backend/tests/Unit/Set/UseCases/CreateSetTest.php b/backend/tests/Unit/Set/UseCases/CreateSetTest.php
new file mode 100644
index 0000000..bd3c9f4
--- /dev/null
+++ b/backend/tests/Unit/Set/UseCases/CreateSetTest.php
@@ -0,0 +1,63 @@
+<?php
+
+namespace Tests\Unit\Set\UseCases;
+
+use App\Exceptions\BadRequestException;
+use App\Set\Set as DomainSet;
+use App\Set\UseCases\CreateSet\CreateSet;
+use App\Set\UseCases\CreateSet\CreateSetRequest;
+use Tests\Fakes\FakeElementRepository;
+use Tests\Fakes\FakeSetRepository;
+use Tests\TestCase;
+
+class CreateSetTest extends TestCase
+{
+    private FakeSetRepository $setRepo;
+
+    private FakeElementRepository $elementRepo;
+
+    private CreateSet $createSet;
+
+    protected function setUp(): void
+    {
+        $this->setRepo = new FakeSetRepository();
+        $this->elementRepo = new FakeElementRepository();
+        $this->createSet = new CreateSet(
+            $this->setRepo,
+            $this->elementRepo,
+        );
+    }
+
+    public function testCreatesSet(): void
+    {
+        $set = $this->createSet->execute(
+            new CreateSetRequest('Daily learning')
+        );
+
+        $this->assertInstanceOf(DomainSet::class, $set);
+        $this->assertSame(1, $set->getId());
+        $this->assertSame('Daily learning', $set->getName());
+    }
+
+    public function testCreatesRootElementForSet(): void
+    {
+        $set = $this->createSet->execute(
+            new CreateSetRequest('Daily learning')
+        );
+
+        $elements = $this->elementRepo->findBySetId($set->getId());
+
+        $this->assertCount(1, $elements);
+        $this->assertSame('Daily learning', $elements[0]->getTitle());
+        $this->assertSame($set->getId(), $elements[0]->getSet()->getId());
+        $this->assertNull($elements[0]->getParentElement());
+    }
+
+    public function testThrowsWhenNameMissing(): void
+    {
+        $this->expectException(BadRequestException::class);
+        $this->expectExceptionMessage('name is required');
+
+        $this->createSet->execute(new CreateSetRequest(null));
+    }
+}