MC-40920: Empty request to graphql in 2.4.2 throws 500 instead of previous 200

Author: tsviklinskyi

app/code/Magento/GraphQl/Test/Unit/Controller/HttpRequestValidator/HttpVerbValidatorTest.php

@@ -0,0 +1,97 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\GraphQl\Test\Unit\Controller\HttpRequestValidator;
+
+use Magento\Framework\App\HttpRequestInterface;
+use Magento\Framework\TestFramework\Unit\Helper\ObjectManager;
+use Magento\GraphQl\Controller\HttpRequestValidator\HttpVerbValidator;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Test HttpVerbValidator
+ */
+class HttpVerbValidatorTest extends TestCase
+{
+    /**
+     * @var HttpVerbValidator|MockObject
+     */
+    private $httpVerbValidator;
+
+    /**
+     * @var HttpRequestInterface|MockObject
+     */
+    private $requestMock;
+
+    /**
+     * @inheritDoc
+     */
+    protected function setup(): void
+    {
+        $objectManager = new ObjectManager($this);
+        $this->requestMock = $this->getMockBuilder(HttpRequestInterface::class)
+            ->disableOriginalConstructor()
+            ->onlyMethods(
+                [
+                    'isPost',
+                ]
+            )->addMethods(
+                [
+                    'getParam',
+                ]
+            )
+            ->getMockForAbstractClass();
+
+        $this->httpVerbValidator = $objectManager->getObject(
+            HttpVerbValidator::class
+        );
+    }
+
+    /**
+     * Test for validate method
+     *
+     * @param string $query
+     * @param bool $needException
+     * @dataProvider validateDataProvider
+     */
+    public function testValidate(string $query, bool $needException): void
+    {
+        $this->requestMock
+            ->expects($this->once())
+            ->method('isPost')
+            ->willReturn(false);
+
+        $this->requestMock
+            ->method('getParam')
+            ->with('query', '')
+            ->willReturn($query);
+
+        if ($needException) {
+            $this->expectExceptionMessage('Syntax Error: Unexpected <EOF>');
+        }
+
+        $this->httpVerbValidator->validate($this->requestMock);
+    }
+
+    /**
+     * @return array
+     */
+    public function validateDataProvider(): array
+    {
+        return [
+            [
+                'query' => '',
+                'needException' => false,
+            ],
+            [
+                'query' => ' ',
+                'needException' => true
+            ],
+        ];
+    }
+}