GH-26255: Add test coverage for multi-request purge tag splitting.

Author: Matthew O'Loughlin

app/code/Magento/CacheInvalidate/Model/PurgeCache.php

@@ -9,7 +9,6 @@
 
 /**
  * Class PurgeCache
- * @package Magento\CacheInvalidate\Model
  */
 class PurgeCache
 {
@@ -54,7 +53,7 @@ public function __construct(
         \Magento\PageCache\Model\Cache\Server $cacheServer,
         \Magento\CacheInvalidate\Model\SocketFactory $socketAdapterFactory,
         InvalidateLogger $logger,
-        $maxHeaderSize = 7680
+        int $maxHeaderSize = 7680
     ) {
         $this->cacheServer = $cacheServer;
         $this->socketAdapterFactory = $socketAdapterFactory;

app/code/Magento/CacheInvalidate/Test/Unit/Model/PurgeCacheTest.php

@@ -42,6 +42,7 @@ protected function setUp()
                 'cacheServer' => $this->cacheServer,
                 'socketAdapterFactory' => $socketFactoryMock,
                 'logger' => $this->loggerMock,
+                'maxHeaderSize' => 256
             ]
         );
     }
@@ -85,6 +86,49 @@ public function testSendPurgeRequest($hosts)
         $this->assertTrue($this->model->sendPurgeRequest(['tags']));
     }
 
+    public function testSendMultiPurgeRequest()
+    {
+        $tags = [
+            '(^|,)cat_p_95(,|$)', '(^|,)cat_p_96(,|$)', '(^|,)cat_p_97(,|$)', '(^|,)cat_p_98(,|$)',
+            '(^|,)cat_p_99(,|$)', '(^|,)cat_p_100(,|$)', '(^|,)cat_p_10038(,|$)', '(^|,)cat_p_142985(,|$)',
+            '(^|,)cat_p_199(,|$)', '(^|,)cat_p_300(,|$)', '(^|,)cat_p_12038(,|$)', '(^|,)cat_p_152985(,|$)',
+            '(^|,)cat_p_299(,|$)', '(^|,)cat_p_400(,|$)', '(^|,)cat_p_13038(,|$)', '(^|,)cat_p_162985(,|$)',
+        ];
+
+        $tagsSplitA = array_slice($tags, 0, 12);
+        $tagsSplitB = array_slice($tags, 12, 4);
+
+        $uri =  UriFactory::factory('')->setHost('localhost')
+            ->setPort(80)
+            ->setScheme('http');
+
+        $this->cacheServer->expects($this->once())
+            ->method('getUris')
+            ->willReturn([$uri]);
+
+        $this->socketAdapterMock->expects($this->exactly(2))
+            ->method('connect')
+            ->with($uri->getHost(), $uri->getPort());
+
+        $this->socketAdapterMock->expects($this->exactly(2))
+            ->method('write')
+            ->withConsecutive(
+                [
+                    'PURGE', $uri, '1.1',
+                    ['X-Magento-Tags-Pattern' => implode('|', $tagsSplitA), 'Host' => $uri->getHost()]
+                ],
+                [
+                    'PURGE', $uri, '1.1',
+                    ['X-Magento-Tags-Pattern' => implode('|', $tagsSplitB), 'Host' => $uri->getHost()]
+                ]
+            );
+
+        $this->socketAdapterMock->expects($this->exactly(2))
+            ->method('close');
+
+        $this->assertTrue($this->model->sendPurgeRequest($tags));
+    }
+
     /**
      * @return array
      */