Add unit tests

src/Registry/ElementRegistry.php

@@ -11,6 +11,7 @@
 
 use function array_merge_recursive;
 use function dirname;
+use function file_exists;
 
 final class ElementRegistry
 {
@@ -26,11 +27,13 @@ final private function __construct()
         // Initialize the registry with all the elements we know
         $classesDir = dirname(__FILE__, 3) . '/vendor/simplesamlphp/composer-xmlprovider-installer/classes';
 
-        $finder = Finder::create()->files()->name('element.registry.*.php')->in($classesDir);
-        if ($finder->hasResults()) {
-            foreach ($finder as $file) {
-                $elements = include($file);
-                $this->registry = array_merge_recursive($this->registry, $elements);
+        if (file_exists($classesDir) === true) {
+            $finder = Finder::create()->files()->name('element.registry.*.php')->in($classesDir);
+            if ($finder->hasResults()) {
+                foreach ($finder as $file) {
+                    $elements = include($file);
+                    $this->registry = array_merge_recursive($this->registry, $elements);
+                }
             }
         }
     }

tests/Registry/ElementRegistryTest.php

@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\Test\XML;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\TestCase;
+use SimpleSAML\XML\Registry\ElementRegistry;
+
+/**
+ * @package simplesamlphp\xml-common
+ */
+#[CoversClass(ElementRegistry::class)]
+#[Group('registry')]
+final class ElementRegistryTest extends TestCase
+{
+    /** @var \SimpleSAML\XML\Registry\ElementRegistry */
+    protected static ElementRegistry $registry;
+
+
+    /**
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$registry = ElementRegistry::getInstance();
+        self::$registry->registerElementHandler('\SimpleSAML\Test\XML\Element');
+    }
+
+
+    /**
+     */
+    public function testFetchingHandlerWorks(): void
+    {
+        $handler = self::$registry->getElementHandler('urn:x-simplesamlphp:namespace', 'Element');
+        $this->assertEquals($handler, '\SimpleSAML\Test\XML\Element');
+    }
+
+
+    /**
+     */
+    public function testAddingHandlerWorks(): void
+    {
+        self::$registry->registerElementHandler('\SimpleSAML\Test\XML\ExtendableElement');
+        $handler = self::$registry->getElementHandler('urn:x-simplesamlphp:namespace', 'ExtendableElement');
+        $this->assertEquals($handler, '\SimpleSAML\Test\XML\ExtendableElement');
+    }
+
+
+    /**
+     */
+    public function testUnknownHandlerReturnsNull(): void
+    {
+        $handler = self::$registry->getElementHandler('urn:x-simplesamlphp:namespace', 'UnknownElement');
+        $this->assertNull($handler);
+    }
+}