diff --git a/classes/UrlHelper.php b/classes/UrlHelper.php
index e6b3b0aad..d088a355b 100644
--- a/classes/UrlHelper.php
+++ b/classes/UrlHelper.php
@@ -18,7 +18,7 @@ class UrlHelper {
 	static string $fetch_effective_url;
 	static string $fetch_effective_ip_addr;
 
-	private static ?GuzzleHttp\ClientInterface $client = null;
+	public static ?GuzzleHttp\ClientInterface $client = null;
 
 	private static function get_client(): GuzzleHttp\ClientInterface {
 		if (self::$client == null) {
@@ -385,8 +385,7 @@ class UrlHelper {
 
 					// If credentials were provided and we got a 403 back, retry once with auth type 'any'
 					// to attempt compatibility with unusual configurations.
-					if ($login && $pass && self::$fetch_last_error_code === 403
-						&& isset($options['auth_type']) && $options['auth_type'] !== 'any') {
+					if ($login && $pass && self::$fetch_last_error_code === 403 && $auth_type !== 'any') {
 						$options['auth_type'] = 'any';
 						$span->end();
 						return self::fetch($options);
diff --git a/tests/UrlHelperTest.php b/tests/UrlHelperTest.php
index fe4eb5db2..2170ed50b 100644
--- a/tests/UrlHelperTest.php
+++ b/tests/UrlHelperTest.php
@@ -1,5 +1,11 @@
 <?php
 
+use GuzzleHttp\Client;
+use GuzzleHttp\Handler\MockHandler;
+use GuzzleHttp\HandlerStack;
+use GuzzleHttp\Psr7\Response;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\Exception\RequestException;
 use PHPUnit\Framework\TestCase;
 
 final class UrlHelperTest extends TestCase {
@@ -13,16 +19,22 @@ final class UrlHelperTest extends TestCase {
 		// magnet allowed because it's a href attribute
 		$this->assertEquals(
 			'magnet:?xt=urn:btih:...',
-			UrlHelper::rewrite_relative('http://example.com/example/',
+			UrlHelper::rewrite_relative(
+				'http://example.com/example/',
 				'magnet:?xt=urn:btih:...',
-				"a", "href", "")
+				"a",
+				"href",
+				""
+			)
 		);
 
 		// disallowed magnet
 		$this->assertEquals(
 			'http://example.com?xt=urn:btih:...',
-			UrlHelper::rewrite_relative('http://example.com/example/',
-				'magnet:?xt=urn:btih:...')
+			UrlHelper::rewrite_relative(
+				'http://example.com/example/',
+				'magnet:?xt=urn:btih:...'
+			)
 		);
 
 		$this->assertEquals(
@@ -49,6 +61,54 @@ final class UrlHelperTest extends TestCase {
 			'http://www.example.com/test',
 			UrlHelper::rewrite_relative('http://www.example.com/test2 ', 'http://www.example.com/test')
 		);
+	}
 
+	public function test_fetch(): void {
+		$mock = new MockHandler();
+
+		UrlHelper::$client = new Client([
+			'handler' => HandlerStack::create($mock),
+		]);
+
+		$mock->append(new Response(200, [], 'Hello, World'));
+		$result = UrlHelper::fetch('https://www.example.com');
+		$this->assertEquals(200, UrlHelper::$fetch_last_error_code);
+		$this->assertEquals('Hello, World', $result);
+
+		foreach (['ftp://ftp.example.com', 'http://127.0.0.1', 'blah', '', 42, null] as $url) {
+			$result = UrlHelper::fetch($url);
+			$this->assertFalse($result);
+		}
+
+		$mock->append(new Response(200, ['Content-Length' => PHP_INT_MAX]));
+		$result = UrlHelper::fetch('https://www.example.com/very-large-content-length');
+		$this->assertFalse($result);
+
+		$mock->append(new Response(301, ['Location' => 'https://www.example.com']));
+		$result = UrlHelper::fetch(['url' => 'https://example.com', 'followlocation' => false]);
+		$this->assertFalse($result);
+
+		$mock->append(
+			new Response(301, ['Location' => 'http://127.0.0.1']),
+			new Response(200, [], 'Hello, World'),
+		);
+		$result = UrlHelper::fetch(['url' => 'https://example.com', 'followlocation' => true]);
+		$this->assertFalse($result);
+		$this->assertEquals('URL received after redirection failed extended validation.', UrlHelper::$fetch_last_error);
+		$this->assertEquals('http://127.0.0.1', UrlHelper::$fetch_effective_url);
+
+		$mock->append(new Response(200, [], ''));
+		$result = UrlHelper::fetch('https://www.example.com');
+		$this->assertFalse($result);
+		$this->assertEquals('Successful response, but no content was received.', UrlHelper::$fetch_last_error);
+
+		// Currently failing with `Error: Undefined constant "CURLOPT_HTTPAUTH"`.
+		// $mock->append(
+		// 	new Response(403, []),
+		// 	new Response(200, [], 'Hello, World'),
+		// );
+		// $result = UrlHelper::fetch(['url' => 'https://example.com/requires-credentials', 'login' => 'some_username', 'pass' => 'some_password']);
+		// $this->assertEquals(200, UrlHelper::$fetch_last_error_code);
+		// $this->assertEquals('Hello, World', $result);
 	}
 }