public function testClear()
{
$packageFile1 = new PackageFile('vendor/package1');
$package1 = new Package($packageFile1, '/path1');
$packageFile2 = new PackageFile('vendor/package2');
$package2 = new Package($packageFile2, '/path2');
$rootPackageFile = new RootPackageFile('vendor/root');
$rootPackage = new RootPackage($rootPackageFile, '/path3');
$this->collection->add($package1);
$this->collection->add($rootPackage);
$this->collection->add($package2);
$this->collection->clear();
$this->assertFalse($this->collection->contains('vendor/root'));
$this->assertFalse($this->collection->contains('vendor/package1'));
$this->assertFalse($this->collection->contains('vendor/package2'));
$this->assertTrue($this->collection->isEmpty());
}