stream plugin: fix #each loop when used with webmock

when response would be called inside the #each block, the webmock trigger would inject the body before attaching the response object to the request, thereby retriggering #each in a loop

Closes #281

integration_tests/webmock_test.rb

@@ -225,6 +225,21 @@ class WebmockTest < Minitest::Test
     assert_requested(redirect_request)
   end
 
+  def test_webmock_with_stream_plugin_each
+    request = stub_request(:get, MOCK_URL_HTTP).to_return(body: "body")
+
+    body = "".b
+    response = HTTPX.plugin(:stream).get(MOCK_URL_HTTP, stream: true)
+    response.each do |chunk|
+      next if (300..399).cover?(response.status)
+
+      body << chunk
+    end
+
+    assert_equal("body", body)
+    assert_requested(request)
+  end
+
   def test_webmock_with_stream_plugin_each_line
     session = HTTPX.plugin(:stream)
     request = stub_request(:get, MOCK_URL_HTTP).to_return(body: "First line\nSecond line")

lib/httpx/adapters/webmock.rb

@@ -38,12 +38,10 @@ module WebMock
 
           return build_error_response(request, webmock_response.exception) if webmock_response.exception
 
-          response = request.options.response_class.new(request,
+          request.options.response_class.new(request,
                                              webmock_response.status[0],
                                              "2.0",
                                              webmock_response.headers)
-          response << webmock_response.body.dup
-          response
         end
 
         def build_error_response(request, exception)
@@ -90,6 +88,7 @@ module WebMock
             log { "mocking #{request.uri} with #{mock_response.inspect}" }
             request.response = response
             request.emit(:response, response)
+            response << mock_response.body.dup unless response.is_a?(HTTPX::ErrorResponse)
           elsif WebMock.net_connect_allowed?(request_signature.uri)
             if WebMock::CallbackRegistry.any_callbacks?
               request.on(:response) do |resp|