test failure with rack-test 2.0

[terceiro]

If I make this change to Gemfile

diff --git a/Gemfile b/Gemfile
index acc721aa..f0cff687 100644
--- a/Gemfile
+++ b/Gemfile
@@ -31,7 +31,7 @@ group :test do
   gem 'maruku'
   gem 'mime-types'
   gem 'rack-jsonp', require: 'rack/jsonp'
-  gem 'rack-test', '~> 1.1.0'
+  gem 'rack-test', '~> 2.0'
   gem 'rspec', '~> 3.11.0'
   gem 'ruby-grape-danger', '~> 0.2.0', require: false
   gem 'simplecov', '~> 0.21.2'

and run the tests (after running bundle), I get the following test failures:

Failures:

  1) Grape::Endpoint#headers includes request headers
     Failure/Error:
       expect(JSON.parse(last_response.body)).to eq(
         'Host' => 'example.org',
         'Cookie' => ''
       )
     
       expected: {"Cookie"=>"", "Host"=>"example.org"}
            got: {"Cookie"=>"", "Host"=>"example.org", "Version"=>"HTTP/1.0"}
     
       (compared using ==)
     
       Diff:
       @@ -1,3 +1,4 @@
        "Cookie" => "",
        "Host" => "example.org",
       +"Version" => "HTTP/1.0",
       
     # ./spec/grape/endpoint_spec.rb:141:in `block (3 levels) in <top (required)>'

  2) Grape::Endpoint#params from body parameters returns a 400 if given an invalid multipart body
     Failure/Error: expect(last_response.body).to eq('empty message body supplied with multipart/form-data; boundary=foobar content-type')
     
       expected: "empty message body supplied with multipart/form-data; boundary=foobar content-type"
            got: "file is invalid"
     
       (compared using ==)
     # ./spec/grape/endpoint_spec.rb:435:in `block (4 levels) in <top (required)>'

Finished in 4.61 seconds (files took 1.81 seconds to load)
2152 examples, 2 failures

Failed examples:

rspec ./spec/grape/endpoint_spec.rb:139 # Grape::Endpoint#headers includes request headers
rspec ./spec/grape/endpoint_spec.rb:426 # Grape::Endpoint#params from body parameters returns a 400 if given an invalid multipart body

It would be nice if these tests could be made to work with rack-test 2.0.