write a test for `#form_data?`

The initial attempt was to remove the method at all in
https://github.com/sergey-alekseev/rails/commit/4926aa68c98673e7be88a2d2b57d72dc490bc71c.

The method overrides Rack's `#form_data?`
https://github.com/rack/rack/blob/6f8808d4201e68e4bd780441b3b7bb3ee6d1f43e/lib/rack/request.rb#L172-L184.
Which may have some incorrect implementation actually. `type.nil?` isn't possible I suppose. I'll check.

1 files changed, 9 insertions, 1 deletions

diff --git a/actionpack/lib/action_dispatch/http/request.rb b/actionpack/lib/action_dispatch/http/request.rb
index 732ee67268..d8419ad804 100644
--- a/actionpack/lib/action_dispatch/http/request.rb
+++ b/actionpack/lib/action_dispatch/http/request.rb
@@ -282,8 +282,16 @@ module ActionDispatch
       end
     end
 
+    # Determine whether the request body contains form-data by checking
+    # the request Content-Type for one of the media-types:
+    # "application/x-www-form-urlencoded" or "multipart/form-data". The
+    # list of form-data media types can be modified through the
+    # +FORM_DATA_MEDIA_TYPES+ array.
+    #
+    # A request body is not assumed to contain form-data when no
+    # Content-Type header is provided and the request_method is POST.
     def form_data?
-      FORM_DATA_MEDIA_TYPES.include?(content_mime_type.to_s)
+      FORM_DATA_MEDIA_TYPES.include?(media_type)
     end
 
     def body_stream #:nodoc: