ENGCOM-6961: Unit test for CatalogProductCompareClearObserver #26944

 - Merge Pull Request #26944 from mmezhensky/magento2:unittest-CatalogProductCompareClearObserverTest
 - Merged commits:
   1. c7e6795
   2. 15437fc

app/code/Magento/Reports/Test/Unit/Observer/CatalogProductCompareClearObserverTest.php

@@ -0,0 +1,143 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+declare(strict_types=1);
+
+namespace Magento\Reports\Test\Unit\Observer;
+
+use Magento\Framework\Event\Observer;
+use Magento\Framework\TestFramework\Unit\Helper\ObjectManager;
+use Magento\Reports\Model\Event;
+use Magento\Reports\Model\Product\Index\Compared;
+use Magento\Reports\Model\Product\Index\ComparedFactory;
+use Magento\Reports\Model\ReportStatus;
+use Magento\Reports\Observer\CatalogProductCompareClearObserver;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Unit test for Magento\Reports\Test\Unit\Observer\CatalogProductCompareClearObserver
+ */
+class CatalogProductCompareClearObserverTest extends TestCase
+{
+    /**
+     * Testable Object
+     *
+     * @var CatalogProductCompareClearObserver
+     */
+    private $observer;
+
+    /**
+     * @var ObjectManager
+     */
+    private $objectManager;
+
+    /**
+     * @var Observer|MockObject
+     */
+    private $observerMock;
+
+    /**
+     * @var ReportStatus|MockObject
+     */
+    private $reportStatusMock;
+
+    /**
+     * @var ComparedFactory|MockObject
+     */
+    private $productCompFactoryMock;
+
+    /**
+     * @var Compared|MockObject
+     */
+    private $productCompModelMock;
+
+    /**
+     * @var Event|MockObject
+     */
+    private $reportEventMock;
+
+    /**
+     * @inheritDoc
+     */
+    protected function setUp(): void
+    {
+        $this->objectManager = new ObjectManager($this);
+        $this->observerMock = $this->createMock(Observer::class);
+
+        $this->reportStatusMock = $this->getMockBuilder(ReportStatus::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['isReportEnabled'])
+            ->getMock();
+
+        $this->reportEventMock = $this->getMockBuilder(Event::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $this->productCompFactoryMock = $this->getMockBuilder(ComparedFactory::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['create'])
+            ->getMock();
+
+        $this->productCompModelMock = $this->getMockBuilder(Compared::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $this->observer = $this->objectManager->getObject(
+            CatalogProductCompareClearObserver::class,
+            [
+                'reportStatus' => $this->reportStatusMock,
+                'productCompFactory' => $this->productCompFactoryMock
+            ]
+        );
+    }
+
+    /**
+     *  Test for execute(), covers test case for remove all products from compare products
+     */
+    public function testExecuteRemoveProducts(): void
+    {
+        $this->reportStatusMock
+            ->expects($this->once())
+            ->method('isReportEnabled')
+            ->with(Event::EVENT_PRODUCT_VIEW)
+            ->willReturn(true);
+
+        $this->productCompFactoryMock
+            ->expects($this->once())
+            ->method('create')
+            ->willReturn($this->productCompModelMock);
+
+        $this->productCompModelMock
+            ->expects($this->once())
+            ->method('calculate')
+            ->willReturnSelf();
+
+        $this->observer->execute($this->observerMock);
+    }
+
+    /**
+     *  Test for execute(), covers test case for remove all products from compare products with report disabled
+     */
+    public function testExecuteRemoveProductsWithReportDisable(): void
+    {
+        $this->reportStatusMock
+            ->expects($this->once())
+            ->method('isReportEnabled')
+            ->with(Event::EVENT_PRODUCT_VIEW)
+            ->willReturn(false);
+
+        $this->productCompFactoryMock
+            ->expects($this->never())
+            ->method('create');
+
+        $this->productCompModelMock
+            ->expects($this->never())
+            ->method('calculate');
+
+        $this->observer->execute($this->observerMock);
+    }
+}