[POC] Added validation

[dantleech]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	no
Deprecations?	no
Tests pass?	N/A (yet)
Fixed tickets	N/A
License	MIT
Doc PR	N/A

I was scratching my head for a while when I uploaded files using the test application - I was getting a File '' not found message. Turns out the file exceeded my max_filesize.

This PR implements the validate method in UploadFileHelper. I also prepared a symfony PR as I think it would be a better place to have this in some way (currently the various UPLOADERR* constants are checked only in the Validation component).

But I wanted to validate the idea here first.

[lsmith77]

/cc @rmsint (not sure if you get a notification when i assign a ticket to you)

[rmsint]

Having this validation is a lot better for the user yes. I think we should decide whether to include this untill Symfony has this change. I am +1.

And then what needs to be done to merge, I propose:

• adding a unit test for the validation (if easily possible)
• check translations
• check if we need to relate the error to a form field, like when using the cmf_media_image form type
• (optionally) update demo test case to use a flash message to display the errors

[lsmith77]

@dantleech can you wrap up the open issues?

[dantleech]

@rmsint I don't think we need to worry about translations, these are Exception messages of last resort, the developer should add validation if they want the user to see nice error messages.

[dantleech]

Added test case. Note that there are some unrelated failures todo with jackalope doctrine_dbal which are preventing me checking this in the Test App, or checking the WebTestCase.

[lsmith77]

fyi .. tests finally ran through on travis https://travis-ci.org/symfony-cmf/MediaBundle/jobs/11835565#L191

[dantleech]

ok, the tests should be fine again now. I have added a config option to disable the "is_uploaded_file" check, enabling us to disable this check when in the test environment.

[lsmith77]

needs a rebase

[lsmith77]

closing in favor of #72