Testing MessageValidator::lintMessage method

[Djuki]

Improving test coverage #39

I tested the method MessageValidator::lintMessage, and this PR is not ready for the test since test is not green.

I will explain why. I tested only this method, isolated, that is why I only test his responses.

If the message is valid lintMessage will return an empty string, if it is not valid it will return string error message. NOTE: It will not throw an Exception, which can be expected IMHO. This is why MessageValidator::lintMessage can't catch the \Seld\JsonLint\ParsingException and this method always return an empty string, even for not valid messages.

Method lint in \Seld\JsonLint\JsonParser class will return null if message is valid, and if message is not valid it will return Exception object.

We can talk about the design of this classes if you want, or we can just discuss expectation in test method invalidJsonMessage. I expect to get the error message if the message is not valid. If would be better to throw the exception instead of returning error string IMHO.

What are next steps about this issue?

[kocsismate]

Thank you really much for this detailed explanation! And I like the way you use data providers, I haven't been aware of them until now :) I'll try to answer appropriately during the weekend.

[kocsismate]

OK, at last I had time to understand the problem. I am glad that you chose this class to test and found important issues here. :)

You are absolutely right, the linter should throw an exception. But the thing is, the MessageValidator::lintMessage() method is only used by two classes which extend MessageValidator and they will emit an exception correctly. That means MessageValidator::lintMessage() should be protected instead (I can't imagine why I left it as public). In this case I think it is OK for it not to raise an exception.

Furthermore, MessageValidator::lintMessage() will return null if the message is empty which behaviour is really silly, so an empty string would be the appropriate return value.

What do you think about my reasoning?

If you still have some time in the near future then I will happily wait for you to finish the PR, otherwise I can also take it over from you.

[Djuki]

Ok. I will prepare new changes and unit tests soon.

[Djuki]

@kocsismate MessageValidator is changed by your request. All methods are protected, and we do not need to test this class anymore.

[Djuki]

I had to fix this method since it was returning true for any kind of header. After this change, it returns TRUE only if the header line is application/vnd.api+json. If this is how it should behave than my change is correct.

[kocsismate]

Thank you for your work! I'll merge your changes and take care of the rest! Have a nice Hacktober! :)