public function testNotPrependWhenNull()
{
$containerBuilderProphecy = $this->prophesize(ContainerBuilder::class);
$containerBuilderProphecy->getExtensionConfig('framework')->willReturn(null)->shouldBeCalled();
$containerBuilderProphecy->prependExtensionConfig('framework', Argument::type('array'))->shouldNotBeCalled();
$containerBuilder = $containerBuilderProphecy->reveal();
$this->extension->prepend($containerBuilder);
}