handle headers as both strings and arrays

[kellyselden]

When I don't supply the express response in the visit options, everything works fine, but when I do supply it:

app.visit(url, {
  response: res
})

The headers parsing fails because sometimes the header values are already arrays and don't have the split function. A sample while debugging:

// values masked...
debug> exec headers
{ 'set-cookie': 
   [ 'ident=14xxxxxxxxx24; Max-Age=1800; Doma... (length: 160)',
     'session=0xxxxxxxxD; Domain=test.com; Path=/;... (length: 89)' ],
  'x-session-id': '5xxxxxxxxx4',
  'x-registration-id': '8xxxxxxx4',
  'x-appserver-id': 'test',
  token: 'eyJhbGciOiJIUzxxxxxxxxxxxxxxxxxRDVGQkR... (length: 1636)' }

I don't yet know if this is an issue only I would have for some reason, or it will start turning up in other apps.

[kellyselden]

I should add that I'm using the standalone fastboot package, without any middleware.

[arjansingh]

Other than the type checking for a string... LGTM.

[arjansingh]

I'd prefer doing an instanceof or typeof check here instead.

[kellyselden]

changed.

[kellyselden]

I finally found the evidence needed to get this merged. Express turns the set-cookie response header into an array if you set more than one cookie:

https://github.com/expressjs/express/blob/bd47aeb88d28c6cff6e2d8e5378ec73c262e039f/lib/response.js#L805
https://github.com/expressjs/express/blob/bd47aeb88d28c6cff6e2d8e5378ec73c262e039f/lib/response.js#L682

[kellyselden]

cc @danmcclain and @tomdale, I remember on the call you two expressed concern over this change.

[rwjblue]

closed by #113