Extract text node collapsing into a separate class for easier testing

src/Inline/AdjoiningTextCollapser.php

@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * This file is part of the league/commonmark package.
+ *
+ * (c) Colin O'Dell <colinodell@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace League\CommonMark\Inline;
+
+use League\CommonMark\Inline\Element\Text;
+use League\CommonMark\Node\Node;
+
+/**
+ * @internal
+ */
+final class AdjoiningTextCollapser
+{
+    /**
+     * @param Node $container
+     *
+     * @internal
+     */
+    public static function collapseTextNodes(Node $container)
+    {
+        $walker = $container->walker();
+        while (($event = $walker->next()) !== null) {
+            if ($event->isEntering()) {
+                $node = $event->getNode();
+                if ($node instanceof Text) {
+                    while (($next = $node->next()) && $next instanceof Text) {
+                        $node->append($next->getContent());
+                        $next->detach();
+                    }
+                }
+            }
+        }
+    }
+}

src/InlineParserEngine.php

@@ -14,6 +14,7 @@
 
 namespace League\CommonMark;
 
+use League\CommonMark\Inline\AdjoiningTextCollapser;
 use League\CommonMark\Inline\Element\Text;
 use League\CommonMark\Node\Node;
 use League\CommonMark\Reference\ReferenceMap;
@@ -42,7 +43,7 @@ public function parse(Node $container, ReferenceMap $referenceMap)
 
         $this->processInlines($inlineParserContext);
 
-        $this->collapseAdjoiningTextElements($inlineParserContext);
+        AdjoiningTextCollapser::collapseTextNodes($container);
     }
 
     /**
@@ -100,21 +101,4 @@ private function addPlainText($character, Node $container, InlineParserContext $
             $container->appendChild(new Text($text));
         }
     }
-
-    private function collapseAdjoiningTextElements(InlineParserContext $context)
-    {
-        $walker = $context->getContainer()->walker();
-
-        while (($event = $walker->next()) !== null) {
-            if ($event->isEntering()) {
-                $node = $event->getNode();
-                if ($node instanceof Text) {
-                    while (($next = $node->next()) && $next instanceof Text) {
-                        $node->append($next->getContent());
-                        $next->detach();
-                    }
-                }
-            }
-        }
-    }
 }