public function testApiRegisterProvider_RegistersProviderImmediately_WhenRegisterIsAlreadyBooted()
{
$register = $this->createRegister();
$provider = $this->getMock(AProvider::class);
$provider->expects($this->once())->method('registerProvider');
$this->setProtectedProperty($register, 'booted', true);
$register->registerProvider($provider);
$this->assertSame([$provider], $this->getProtectedProperty($register, 'serviceProviders'));
}