/**
  * Test FilesystemHelper::symlinkDir().
  */
 public function testSymlinkDir()
 {
     $testTarget = $this->tempDir();
     $testLink = $this->tempDir() . '/link';
     $this->filesystemHelper->symLink($testTarget, $testLink);
     $this->assertTrue(is_link($testLink));
     touch($testTarget . '/test-file');
     $this->assertFileExists($testLink . '/test-file');
 }