private function mockPackage(array $extras = [])
{
$package = $this->getMock('Composer\\Package\\PackageInterface');
$package->expects($this->any())->method('getTargetDir')->willReturn('');
$package->expects($this->any())->method('getName')->willReturn('foo/bar');
$package->expects($this->any())->method('getPrettyName')->willReturn('foo/bar');
$package->expects(empty($extras) ? $this->any() : $this->atLeastOnce())->method('getExtra')->willReturn($extras);
return $package;
}