diff --git a/spec/services/notes/diff_position_update_service_spec.rb b/spec/services/notes/diff_position_update_service_spec.rb
index 0bca3ea1a09035ee1c9cffa42f809d83819a445d..110efb54fa04906fd21fcaf4768e70b039a67b71 100644
--- a/spec/services/notes/diff_position_update_service_spec.rb
+++ b/spec/services/notes/diff_position_update_service_spec.rb
@@ -32,6 +32,110 @@ describe Notes::DiffPositionUpdateService, services: true do
     )
   end
 
+  # old diff:
+  #     1 + require 'fileutils'
+  #     2 + require 'open3'
+  #     3 +
+  #     4 + module Popen
+  #     5 +   extend self
+  #     6 +
+  #     7 +   def popen(cmd, path=nil)
+  #     8 +     unless cmd.is_a?(Array)
+  #     9 +       raise "System commands must be given as an array of strings"
+  #    10 +     end
+  #    11 +
+  #    12 +     path ||= Dir.pwd
+  #    13 +     vars = { "PWD" => path }
+  #    14 +     options = { chdir: path }
+  #    15 +
+  #    16 +     unless File.directory?(path)
+  #    17 +       FileUtils.mkdir_p(path)
+  #    18 +     end
+  #    19 +
+  #    20 +     @cmd_output = ""
+  #    21 +     @cmd_status = 0
+  #    22 +     Open3.popen3(vars, *cmd, options) do |stdin, stdout, stderr, wait_thr|
+  #    23 +       @cmd_output << stdout.read
+  #    24 +       @cmd_output << stderr.read
+  #    25 +       @cmd_status = wait_thr.value.exitstatus
+  #    26 +     end
+  #    27 +
+  #    28 +     return @cmd_output, @cmd_status
+  #    29 +   end
+  #    30 + end
+  #
+  # new diff:
+  #     1 + require 'fileutils'
+  #     2 + require 'open3'
+  #     3 +
+  #     4 + module Popen
+  #     5 +   extend self
+  #     6 +
+  #     7 +   def popen(cmd, path=nil)
+  #     8 +     unless cmd.is_a?(Array)
+  #     9 +       raise RuntimeError, "System commands must be given as an array of strings"
+  #    10 +     end
+  #    11 +
+  #    12 +     path ||= Dir.pwd
+  #    13 +
+  #    14 +     vars = {
+  #    15 +       "PWD" => path
+  #    16 +     }
+  #    17 +
+  #    18 +     options = {
+  #    19 +       chdir: path
+  #    20 +     }
+  #    21 +
+  #    22 +     unless File.directory?(path)
+  #    23 +       FileUtils.mkdir_p(path)
+  #    24 +     end
+  #    25 +
+  #    26 +     @cmd_output = ""
+  #    27 +     @cmd_status = 0
+  #    28 +
+  #    29 +     Open3.popen3(vars, *cmd, options) do |stdin, stdout, stderr, wait_thr|
+  #    30 +       @cmd_output << stdout.read
+  #    31 +       @cmd_output << stderr.read
+  #    32 +       @cmd_status = wait_thr.value.exitstatus
+  #    33 +     end
+  #    34 +
+  #    35 +     return @cmd_output, @cmd_status
+  #    36 +   end
+  #    37 + end
+  #
+  # old->new diff:
+  # .. .. @@ -6,12 +6,18 @@ module Popen
+  #  6  6
+  #  7  7    def popen(cmd, path=nil)
+  #  8  8      unless cmd.is_a?(Array)
+  #  9    -      raise "System commands must be given as an array of strings"
+  #     9 +      raise RuntimeError, "System commands must be given as an array of strings"
+  # 10 10      end
+  # 11 11
+  # 12 12      path ||= Dir.pwd
+  # 13    -    vars = { "PWD" => path }
+  # 14    -    options = { chdir: path }
+  #    13 +
+  #    14 +    vars = {
+  #    15 +      "PWD" => path
+  #    16 +    }
+  #    17 +
+  #    18 +    options = {
+  #    19 +      chdir: path
+  #    20 +    }
+  # 15 21
+  # 16 22      unless File.directory?(path)
+  # 17 23        FileUtils.mkdir_p(path)
+  # 18 24      end
+  # 19 25
+  # 20 26      @cmd_output = ""
+  # 21 27      @cmd_status = 0
+  #    28 +
+  # 22 29      Open3.popen3(vars, *cmd, options) do |stdin, stdout, stderr, wait_thr|
+  # 23 30        @cmd_output << stdout.read
+  # 24 31        @cmd_output << stderr.read
+  # .. ..
+
   describe "#execute" do
     let(:note) { create(:diff_note_on_merge_request, project: project, position: old_position) }