Let TestResponse assign a parser.

Previously we'd only assign a response parser when a request came through
Action Dispatch integration tests. This made calls to `parsed_body` when a TestResponse
was manually instantiated — though own doing or perhaps from a framework — unintentionally
blow up because no parser was set at that time.

The response can lookup a parser entirely through its own ivars. Extract request encoder to
its own file and assume that a viable content type is present at TestResponse instantiation.

Since the default response parser is a no-op, making `parsed_body` equal to `body`, no
exceptions will be thrown.

1 files changed, 8 insertions, 0 deletions

diff --git a/actionpack/test/dispatch/test_response_test.rb b/actionpack/test/dispatch/test_response_test.rb
index a4f9d56a6a..72e06b4590 100644
--- a/actionpack/test/dispatch/test_response_test.rb
+++ b/actionpack/test/dispatch/test_response_test.rb
@@ -17,4 +17,12 @@ class TestResponseTest < ActiveSupport::TestCase
     assert_response_code_range 500..599, :server_error?
     assert_response_code_range 400..499, :client_error?
   end
+
+  test "response parsing" do
+    response = ActionDispatch::TestResponse.create(200, {}, '')
+    assert_equal response.body, response.parsed_body
+
+    response = ActionDispatch::TestResponse.create(200, { 'Content-Type' => 'application/json' }, '{ "foo": "fighters" }')
+    assert_equal({ 'foo' => 'fighters' }, response.parsed_body)
+  end
 end