diff --git a/src/Composer/Installer/NoopInstaller.php b/src/Composer/Installer/NoopInstaller.php
new file mode 100644
index 000000000..b37329c6f
--- /dev/null
+++ b/src/Composer/Installer/NoopInstaller.php
@@ -0,0 +1,92 @@
+<?php
+
+/*
+ * This file is part of Composer.
+ *
+ * (c) Nils Adermann <naderman@naderman.de>
+ *     Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Composer\Installer;
+
+use Composer\IO\IOInterface;
+use Composer\Downloader\DownloadManager;
+use Composer\Repository\InstalledRepositoryInterface;
+use Composer\Package\PackageInterface;
+use Composer\Util\Filesystem;
+
+/**
+ * Does not install anything but marks packages installed in the repo
+ *
+ * Useful for dry runs
+ *
+ * @author Jordi Boggiano <j.boggiano@seld.be>
+ */
+class NoopInstaller implements InstallerInterface
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function supports($packageType)
+    {
+        return true;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function isInstalled(InstalledRepositoryInterface $repo, PackageInterface $package)
+    {
+        return $repo->hasPackage($package);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function install(InstalledRepositoryInterface $repo, PackageInterface $package)
+    {
+        if (!$repo->hasPackage($package)) {
+            $repo->addPackage(clone $package);
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function update(InstalledRepositoryInterface $repo, PackageInterface $initial, PackageInterface $target)
+    {
+        if (!$repo->hasPackage($initial)) {
+            throw new \InvalidArgumentException('Package is not installed: '.$initial);
+        }
+
+        if (!$repo->hasPackage($target)) {
+            $repo->addPackage(clone $target);
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function uninstall(InstalledRepositoryInterface $repo, PackageInterface $package)
+    {
+        if (!$repo->hasPackage($package)) {
+            // TODO throw exception again here, when update is fixed and we don't have to remove+install (see #125)
+            return;
+            throw new \InvalidArgumentException('Package is not installed: '.$package);
+        }
+        $repo->removePackage($package);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function getInstallPath(PackageInterface $package)
+    {
+        $targetDir = $package->getTargetDir();
+
+        return $package->getPrettyName() . ($targetDir ? '/'.$targetDir : '');
+    }
+}