Fixed obscure code

src/Composer/Autoload/AutoloadGenerator.php

@@ -54,7 +54,7 @@ EOF;
 
         $filesystem = new Filesystem();
         $vendorPath = strtr(realpath($installationManager->getVendorPath()), '\\', '/');
-        $relVendorPath = ltrim(substr($vendorPath, strlen(getcwd())), '/');
+        $relVendorPath = $filesystem->findShortestPath(getcwd(), $vendorPath);
         $vendorDirCode = $filesystem->findShortestPathCode(realpath($targetDir), $vendorPath, true);
 
         $namespacesFile = <<<EOF

tests/Composer/Test/Autoload/AutoloadGeneratorTest.php

@@ -77,6 +77,12 @@ class AutoloadGeneratorTest extends \PHPUnit_Framework_TestCase
         $this->assertAutoloadFiles('main', $this->vendorDir.'/.composer');
     }
 
+    public function testVendorDirSameAsWorkingDir()
+    {
+        chdir($this->vendorDir);
+        $this->testMainPackageAutoloading();
+    }
+
     public function testMainPackageAutoloadingAlternativeVendorDir()
     {
         $package = new MemoryPackage('a', '1.0', '1.0');