Add Domain\Service\Filesystem\FilesystemInterface::isLink().

src/Domain/Service/Filesystem/FilesystemInterface.php

@@ -36,6 +36,17 @@ public function copy(PathInterface $source, PathInterface $destination): void;
      */
     public function exists(PathInterface $path): bool;
 
+    /**
+     * Determines whether the given path is a symbolic link.
+     *
+     * @param \PhpTuf\ComposerStager\Domain\Value\Path\PathInterface $path
+     *   A path to test.
+     *
+     * @return bool
+     *   Returns true if the filename exists and is a symbolic link, false otherwise.
+     */
+    public function isLink(PathInterface $path): bool;
+
     /**
      * Determines whether the given path is writable.
      *

src/Infrastructure/Service/Filesystem/Filesystem.php

@@ -55,6 +55,11 @@ public function exists(PathInterface $path): bool
         return $this->symfonyFilesystem->exists($path->resolve());
     }
 
+    public function isLink(PathInterface $path): bool
+    {
+        return is_link($path->resolve());
+    }
+
     public function isWritable(PathInterface $path): bool
     {
         return is_writable($path->resolve()); // @codeCoverageIgnore

tests/PHPUnit/Infrastructure/Service/Filesystem/FilesystemFunctionalTest.php

@@ -8,7 +8,16 @@
 use Symfony\Component\Filesystem\Exception\IOException as SymfonyIOException;
 use Symfony\Component\Filesystem\Filesystem as SymfonyFilesystem;
 
-/** @coversNothing */
+/**
+ * @coversDefaultClass \PhpTuf\ComposerStager\Infrastructure\Service\Filesystem\Filesystem
+ *
+ * @uses \PhpTuf\ComposerStager\Infrastructure\Factory\Path\PathFactory
+ * @uses \PhpTuf\ComposerStager\Infrastructure\Service\Filesystem\Filesystem
+ * @uses \PhpTuf\ComposerStager\Infrastructure\Value\Path\AbstractPath
+ * @uses \PhpTuf\ComposerStager\Infrastructure\Value\Path\UnixLikePath
+ * @uses \PhpTuf\ComposerStager\Infrastructure\Value\Path\WindowsPath
+ * @uses \Symfony\Component\Filesystem\Filesystem
+ */
 final class FilesystemFunctionalTest extends TestCase
 {
     private const SOURCE_DIR = self::TEST_ENV . DIRECTORY_SEPARATOR . 'source';
@@ -38,6 +47,7 @@ protected function createSut(): Filesystem
         return $filesystem;
     }
 
+    /** @covers ::copy */
     public function testCopy(): void
     {
         $filename = 'file.txt';
@@ -54,12 +64,53 @@ public function testCopy(): void
         self::assertDirectoryListing(self::DESTINATION_DIR, [$filename]);
     }
 
+    /**
+     * @covers ::isLink
+     *
+     * @dataProvider providerIsLink
+     */
+    public function testIsLink(array $files, array $links, bool $expected): void
+    {
+        self::createFiles(self::SOURCE_DIR, $files);
+        self::createSymlinks(self::SOURCE_DIR, $links);
+
+        $sut = $this->createSut();
+
+        $path = self::SOURCE_DIR . DIRECTORY_SEPARATOR . 'link.txt';
+        $actual = $sut->isLink(PathFactory::create($path));
+
+        self::assertSame($expected, $actual, 'Correctly determined whether path was a link.');
+    }
+
+    public function providerIsLink(): array
+    {
+        return [
+            'File is a link' => [
+                'files' => ['target.txt'],
+                'links' => ['link.txt' => 'target.txt'],
+                'expected' => true,
+            ],
+            'File is not a link' => [
+                'files' => ['file.txt'],
+                'links' => [],
+                'expected' => false,
+            ],
+            'No file there' => [
+                'files' => [],
+                'links' => [],
+                'expected' => false,
+            ],
+        ];
+    }
+
     /**
      * Our filesystem service currently depends on the Symfony Filesystem component
      * and currently delegates its copy() method directly to it. Therefore, it is
      * precisely equivalent to its implementation. Symfony's copy() documentation
      * does not specify whether it supports directories as well as files. This
      * test is to discover whether it does. (At this time it does not.)
+     *
+     * @coversNothing
      */
     public function testSymfonyCopyDirectory(): void
     {

tests/PHPUnit/TestCase.php

@@ -105,8 +105,14 @@ protected static function createSymlink(string $baseDir, string $link, string $t
         $link = PathFactory::create("{$baseDir}/{$link}")->resolve();
         $target = PathFactory::create("{$baseDir}/{$target}")->resolve();
         static::ensureParentDirectory($link);
-        $filesystem = new Filesystem();
-        $filesystem->symlink($target, $link);
+
+        // If the symlink target doesn't exist, the tests will pass on Unix-like
+        // systems but fail on Windows. Avoid hard-to-debug problems by making
+        // sure it fails everywhere in that case.
+        assert(file_exists($target), 'Symlink targets exists.');
+
+        symlink($target, $link);
+
         assert(is_link($link), "Created symlink at {$link}.");
     }