1 files changed, 31 insertions, 3 deletions
diff --git a/actionpack/test/dispatch/response_test.rb b/actionpack/test/dispatch/response_test.rb
index 187b9a2420..48342e252a 100644
--- a/actionpack/test/dispatch/response_test.rb
+++ b/actionpack/test/dispatch/response_test.rb
@@ -1,4 +1,6 @@
 require 'abstract_unit'
+require 'timeout'
+require 'rack/content_length'
 
 class ResponseTest < ActiveSupport::TestCase
   def setup
@@ -220,9 +222,9 @@ class ResponseTest < ActiveSupport::TestCase
     assert @response.respond_to?(:method_missing, true)
   end
 
-  test "can be destructured into status, headers and an enumerable body" do
+  test "can be explicitly destructured into status, headers and an enumerable body" do
     response = ActionDispatch::Response.new(404, { 'Content-Type' => 'text/plain' }, ['Not Found'])
-    status, headers, body = response
+    status, headers, body = *response
 
     assert_equal 404, status
     assert_equal({ 'Content-Type' => 'text/plain' }, headers)
@@ -231,12 +233,38 @@ class ResponseTest < ActiveSupport::TestCase
 
   test "[response].flatten does not recurse infinitely" do
     Timeout.timeout(1) do # use a timeout to prevent it stalling indefinitely
-      status, headers, body = [@response].flatten
+      status, headers, body = assert_deprecated { [@response].flatten }
       assert_equal @response.status, status
       assert_equal @response.headers, headers
       assert_equal @response.body, body.each.to_a.join
     end
   end
+
+  test "compatibility with Rack::ContentLength" do
+    @response.body = 'Hello'
+    app = lambda { |env| @response.to_a }
+    env = Rack::MockRequest.env_for("/")
+
+    status, headers, body = app.call(env)
+    assert_nil headers['Content-Length']
+
+    status, headers, body = Rack::ContentLength.new(app).call(env)
+    assert_equal '5', headers['Content-Length']
+  end
+
+  test "implicit destructuring and Array conversion is deprecated" do
+    response = ActionDispatch::Response.new(404, { 'Content-Type' => 'text/plain' }, ['Not Found'])
+
+    assert_deprecated do
+      status, headers, body = response
+
+      assert_equal 404, status
+      assert_equal({ 'Content-Type' => 'text/plain' }, headers)
+      assert_equal ['Not Found'], body.each.to_a
+    end
+
+    assert_deprecated { response.to_ary }
+  end
 end
 
 class ResponseIntegrationTest < ActionDispatch::IntegrationTest