Validate complete order request

[kayue]

The first step to fix #598 is to perform validation in CompleteOrderAction

[mamazu]

Thanks for your contribution to ShopAPI. I have a question about your pull request: What does it validate at the moment, if you haven't have any validation specified.

[kayue]

@mamazu Ideally it should re-validate inventory availability, which can be implemented later.

Nevertheless, Sylius is meant to be extendable, even the ShopAPI doesn't have any validation specified, it should still perform validation to allower developer to add custom validator.

[kayue]

Also due to inconsistent implementation in action class, error is being return in multiple different formats.

For example, invalid cart token, it returns proper error 400 in PutItemToCartAction:

{
  "code": 400,
  "message": "Validation failed",
  "errors": {
    "token": [
      "Cart does not exist."
    ]
  }
}

However, in CompleteOrderAction it returns error 500 due to lack of validation, which needs to be fixed.

{
  "code": 500,
  "message": "Order with ca5ac343-f09d-4cf0-8d34-374d77cd2ca91 token has not been found."
}

In SummarizeAction it returns error 404

{
  "code": 404,
  "message": "Cart with given id does not exists"
}

[mamazu]

Currently as you found the order complete doesn't validate anything and therefore only asserts that the cart is there (which then will cause an error => 500) We should definitely add the same validators as the other endpoints have as well. Like CartExists and so on.

[lchrusciel]

Hey @kayue,

are you willing to add test for this case?

[lchrusciel]

Suggested change

	ExecutionContextInterface $context
	ExecutionContextInterface $context

[lchrusciel]

Thanks, Ka and Max! 🥇

[kayue]

Thanks @lchrusciel for adding the tests. I didn't know what to test but now I learned.

[lchrusciel]

All credits to @mamazu. I just asked him for help ;)