Fix UploadedFile#new regression

[perlun]

In #210, we tried to fix this but the fix was perhaps not really good enough... So let's relax this check a bit and hopefully unbreak these use cases.

@aebirim, please try the following in your application's Gemfile to see if this now resolves the problem you were seeing.

gem 'rack-test', github: 'rack-test', branch: 'fix/uploaded-file-regression-v2'`

@junaruga and/or @scepticulous, please review.

Closes #211

[perlun]

@joemsak or others, could you check if this PR helps your problem?

[ollieh-m]

@perlun I just encountered the problem that (I think) this is intended to resolve. I've just tried with this branch and I don't think it fixes it.

The issue I believe is at this line in utils.rb:
if value.respond_to?(:original_filename)

Where value is #<Capybara::RackTest::Form::NilUploadedFile:0x007fe6ee86da80 @empty_file=#<Tempfile:/var/folders/9h/hrvm5snd38v55y2qlwn3mnjr0000gn/T/nil_uploaded_file20180116-1014-n8cdmw (closed)>>, this evaluates to true, because it does respond to :original_filename.
So we go to build_file_part, which evaluates this:
<<-EOF --#{MULTIPART_BOUNDARY}\r Content-Disposition: form-data; name="#{parameter_name}"; filename="#{escape(uploaded_file.original_filename)}"\r Content-Type: #{uploaded_file.content_type}\r Content-Length: #{uploaded_file.size}\r \r #{uploaded_file.read}\r EOF
And calling uploaded_file.size is where I get the undefined method size' for nil:NilClasserror. (Method_missing tries to sendsizetotempfile, but tempfile` is blank.)

Is the problem that value.respond_to?(:original_filename) is not an appropriate check where the value is a Capybara::RackTest::Form::NilUploadedFile?

(Disclaimer is that this is my first venture into rack-test so I may well be missing or misunderstanding something.)

[ollieh-m]

Apologies, I have just realised Capybara 2.17 resolves the problem I described above.

[arkhamRejek]

is a new version going to be released ? or should we just pull from master

[perlun]

@PaulBrunache Sorry for the delay, will try to get a new version published asap.

[arkhamRejek]

@perlun no rush man, thank you for all your hard work!

[perlun]

New release out: https://github.com/rack-test/rack-test/releases/tag/v0.8.3 🎉