Fix detection of windows drive letters

Author: TRowbotham

CHANGELOG.md

@@ -1,10 +1,19 @@
 # Changelog
 
+## [Unreleased]
+
+### Fixed
+
+- Detection of windows drive letters
+
 ## [3.1.6] - 2022-08-16
 
 ### Changed
 
 - Forbid C0 control code points and U+007F DEL code point in non-opaque domain names per [whatwg/url#685](https://github.com/whatwg/url/pull/685)
+
+## Fixed
+
 - Fix parsing IPv4-mapped IPv6 addresses due to wrong logical condition
 
 ## [3.1.5] - 2022-01-10

src/Component/Path.php

@@ -7,6 +7,7 @@
 use Rowbot\URL\String\AbstractStringBuffer;
 use Rowbot\URL\String\CodePoint;
 
+use function strlen;
 use function strpbrk;
 
 /**
@@ -19,7 +20,7 @@ class Path extends AbstractStringBuffer
      */
     public function isNormalizedWindowsDriveLetter(): bool
     {
-        return isset($this->string[1])
+        return strlen($this->string) === 2
             && strpbrk($this->string[0], CodePoint::ASCII_ALPHA_MASK) === $this->string[0]
             && $this->string[1] === ':';
     }

tests/PathTest.php

@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rowbot\URL\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Rowbot\URL\Component\Path;
+
+class PathTest extends TestCase
+{
+    public function isNormalizedWindowsDriveLetterProvider(): array
+    {
+        return [
+            ['c:', true],
+            ['c:/', false],
+            ['c:a', false],
+            ['4:', false],
+            ['az:', false],
+            ['a|', false],
+            ['a:|', false],
+            ['', false],
+            ['c:\\', false],
+            ['c:?', false],
+            ['c:#', false],
+            ['c:/f', false],
+        ];
+    }
+
+    /**
+     * @dataProvider isNormalizedWindowsDriveLetterProvider
+     */
+    public function testIsNormalizedWindowsDriveLetter(string $input, bool $expected): void
+    {
+        $s = new Path($input);
+        self::assertSame($expected, $s->isNormalizedWindowsDriveLetter());
+    }
+}