public function testTotalSteps()
 {
     $installer = new DummyInstaller();
     $installers = new InstallerCollection(new InstallOutput());
     $installers->add($installer);
     $installers->add(new DummyInstaller());
     $installers->add(new DummyInstaller());
     $this->assertEquals($installers->sumStepCount(), $installer->stepCount() * 3);
 }