diff --git a/lib/prism/testing/test_response.rb b/lib/prism/testing/test_response.rb
new file mode 100644
index 0000000..13436bf
--- /dev/null
+++ b/lib/prism/testing/test_response.rb
@@ -0,0 +1,68 @@
+module Prism
+  module Testing
+    # Wraps the [status, headers, body] triple a Rack-style app returns so
+    # integration tests can assert on it without touching the raw array.
+    class TestResponse
+      attr_reader :status, :headers, :body
+
+      def initialize(status, headers, body_parts)
+        @status = status
+        @headers = headers
+        # #each (not Array(body_parts)) so a StreamingBody (see
+        # Prism::StreamingBody) is drained into one String just like an
+        # ordinary body Array would be - an integration test asserting on
+        # `response.body` needs the whole thing collected either way, it
+        # just never gets streamed to a real socket one chunk at a time.
+        parts = []
+        body_parts.each { |chunk| parts << chunk }
+        @body = parts.join
+      end
+
+      def content_type
+        headers['Content-Type']
+      end
+
+      def location
+        headers['Location']
+      end
+
+      def success?
+        (200..299).cover?(status)
+      end
+
+      def redirect?
+        (300..399).cover?(status)
+      end
+
+      def not_found?
+        status == 404
+      end
+
+      def client_error?
+        (400..499).cover?(status)
+      end
+
+      def server_error?
+        (500..599).cover?(status)
+      end
+
+      # name => raw (still cookie-encoded) value, one entry per Set-Cookie
+      # line. Multiple Set-Cookie headers are joined with "\n" by
+      # Prism::Response#set_cookie, matching the old Rack convention this
+      # codebase follows.
+      def set_cookies
+        raw = headers['Set-Cookie']
+        return {} unless raw
+
+        raw.split("\n").each_with_object({}) do |line, acc|
+          name, value = line.split(';', 2).first.to_s.split('=', 2)
+          acc[name] = value.to_s if name
+        end
+      end
+
+      def json
+        JSON.parse(body)
+      end
+    end
+  end
+end