Incorrect work of FactoryProvider->has()

[roxblnfk]

README.MD: # Using deferred service providers [link]

// returns false as provider wasn't registered
$container->has(EngineInterface::class); 

// returns SolarEngine, registered in the provider
$engine = $container->get(EngineInterface::class); 

// returns true as provider was registered when EngineInterface was requested from the container
$container->has(EngineInterface::class); 

PSR about has():

1.1.2 Reading from a container
has takes one unique parameter: an entry identifier, which MUST be a string. has MUST return true if an entry identifier is known to the container and false if it is not. If has($id) returns false, get($id) MUST throw a NotFoundExceptionInterface.

3.1. Psr\Container\ContainerInterface

    /**
     * Returns true if the container can return an entry for the given identifier.
     * Returns false otherwise.
     *
     * `has($id)` returning true does not mean that `get($id)` will not throw an exception.
     * It does however mean that `get($id)` will not throw a `NotFoundExceptionInterface`.
     *
     * @param string $id Identifier of the entry to look for.
     *
     * @return bool
     */
    public function has($id);

Method get() must returns true if the container can return an entry for the given identifier.
In our case, it returns false until the first call to get()

[samdark]

Need to cover it with unit test...