Make it possible to add extension from the CommonMarkConverter class

src/CommonMarkConverter.php

@@ -18,6 +18,7 @@
 
 use League\CommonMark\Environment\Environment;
 use League\CommonMark\Extension\CommonMark\CommonMarkCoreExtension;
+use League\CommonMark\Extension\ExtensionInterface;
 
 /**
  * Converts CommonMark-compatible Markdown to HTML.
@@ -43,4 +44,9 @@ public function getEnvironment(): Environment
 
         return $this->environment;
     }
+
+    public function addExtension(ExtensionInterface $extension): void
+    {
+        $this->environment->addExtension($extension);
+    }
 }

tests/unit/CommonMarkConverterTest.php

@@ -20,6 +20,7 @@
 use League\CommonMark\Environment\Environment;
 use League\CommonMark\Exception\UnexpectedEncodingException;
 use League\CommonMark\Extension\CommonMark\CommonMarkCoreExtension;
+use League\CommonMark\Extension\Table\TableExtension;
 use League\CommonMark\Util\HtmlFilter;
 use PHPUnit\Framework\TestCase;
 
@@ -70,4 +71,18 @@ public function testGetEnvironmentReturnsMainEnvironmentClass(): void
 
         $this->assertInstanceOf(Environment::class, $converter->getEnvironment());
     }
+
+    public function testAddExtensionToEnvironment(): void
+    {
+        $converter = new CommonMarkConverter();
+
+        $environment = $converter->getEnvironment();
+
+        $this->assertCount(1, $environment->getExtensions());
+        $this->assertInstanceOf(CommonMarkCoreExtension::class, $environment->getExtensions()[0]);
+
+        $environment->addExtension(new TableExtension());
+        $this->assertCount(2, $environment->getExtensions());
+        $this->assertInstanceOf(TableExtension::class, $environment->getExtensions()[1]);
+    }
 }