Follow relative locations correctly. Fixes #228

lib/rack/test.rb

@@ -194,8 +194,13 @@ def follow_redirect!
           else
             [:get, {}]
           end
+
+        # Compute the next location by appending the location header with the
+        # last request, as per https://tools.ietf.org/html/rfc7231#section-7.1.2
+        next_location = URI.parse(last_request.url) + URI.parse(last_response['Location'])
+
         send(
-          request_method, last_response['Location'], params,
+          request_method, next_location.to_s, params,
           'HTTP_REFERER' => last_request.url,
           'rack.session' => last_request.session
         )

spec/fixtures/fake_app.rb

@@ -20,6 +20,14 @@ class FakeApp < Sinatra::Base
         redirect '/redirected'
       end
 
+      get '/nested/redirect' do
+        [301, { 'location' => 'redirected' }, []]
+      end
+
+      get '/nested/redirected' do
+        'Hello World!'
+      end
+
       post '/redirect' do
         if params['status']
           redirect to('/redirected'), Integer(params['status'])

spec/rack/test_spec.rb

@@ -366,6 +366,16 @@ def close
       expect(last_request.env['HTTP_REFERER']).to eql('http://example.org/redirect')
     end
 
+    it 'follows nested redirects' do
+      get '/nested/redirect'
+
+      expect(last_response.headers['location']).to be == 'redirected'
+      follow_redirect!
+
+      expect(last_response).to be_ok
+      expect(last_request.env['PATH_INFO']).to eq('/nested/redirected')
+    end
+
     it 'does not include params when following the redirect' do
       get '/redirect', 'foo' => 'bar'
       follow_redirect!