public function testApiUnregisterAlias_UnregistersAlias()
{
$register = $this->createRegister();
$alias = 'alias';
$existing = 'existing';
$register->registerAlias($alias, $existing);
$aliases = $this->getProtectedProperty($register, 'serviceAliases');
$this->assertSame([$alias => $existing], $aliases);
$register->unregisterAlias($alias);
$aliases = $this->getProtectedProperty($register, 'serviceAliases');
$this->assertSame([], $aliases);
}