discourse/spec/lib/discourse_diff_spec.rb

# frozen_string_literal: true

require "discourse_diff"

RSpec.describe DiscourseDiff do
  describe "inline_html" do
    it "does not lead to XSS" do
      a = "<test>start</test>"
      b = "<test>end</test>"
      prev = "<div>#{CGI.escapeHTML(a)}</div>"
      cur = "<div>#{CGI.escapeHTML(b)}</div>"

      diff = DiscourseDiff.new(prev, cur)
      expect(diff.inline_html).not_to match(%r{</?test>})
      expect(diff.side_by_side_html).not_to match(%r{</?test>})
    end

    it "returns an empty div when no content is diffed" do
      expect(DiscourseDiff.new("", "").inline_html).to eq("<div class=\"inline-diff\"></div>")
    end

    it "returns the diffed content when there is no difference" do
      before = after = "<p>this is a paragraph</p>"
      expect(DiscourseDiff.new(before, after).inline_html).to eq(
        "<div class=\"inline-diff\"><p>this is a paragraph</p></div>",
      )
    end

    it "adds <ins> tags around added text" do
      before = "<p>this is a paragraph</p>"
      after = "<p>this is a great paragraph</p>"
      expect(DiscourseDiff.new(before, after).inline_html).to eq(
        "<div class=\"inline-diff\"><p>this is a <ins>great </ins>paragraph</p></div>",
      )
    end

    it "adds <del> tags around removed text" do
      before = "<p>this is a great paragraph</p>"
      after = "<p>this is a paragraph</p>"
      expect(DiscourseDiff.new(before, after).inline_html).to eq(
        "<div class=\"inline-diff\"><p>this is a <del>great </del>paragraph</p></div>",
      )
    end

    it "adds .diff-ins class when a paragraph is added" do
      before = "<p>this is the first paragraph</p>"
      after = "<p>this is the first paragraph</p><p>this is the second paragraph</p>"
      expect(DiscourseDiff.new(before, after).inline_html).to eq(
        "<div class=\"inline-diff\"><p>this is the first paragraph</p><p class=\"diff-ins\">this is the second paragraph</p></div>",
      )
    end

    it "adds .diff-del class when a paragraph is removed" do
      before = "<p>this is the first paragraph</p><p>this is the second paragraph</p>"
      after = "<p>this is the second paragraph</p>"
      expect(DiscourseDiff.new(before, after).inline_html).to eq(
        "<div class=\"inline-diff\"><p class=\"diff-del\">this is the first paragraph</p><p>this is the second paragraph</p></div>",
      )
    end

    it "does not break diff on character references" do
      before = "<p>'</p>"
      after = "<p></p>"
      expect(DiscourseDiff.new(before, after).inline_html).to eq(
        "<div class=\"inline-diff\"><p><del>&#39;</del></p></div>",
      )
    end
  end

  describe "side_by_side_html" do
    it "returns two empty divs when no content is diffed" do
      expect(DiscourseDiff.new("", "").side_by_side_html).to eq(
        "<div class=\"revision-content\"></div><div class=\"revision-content\"></div>",
      )
    end

    it "returns the diffed content on both sides when there is no difference" do
      before = after = "<p>this is a paragraph</p>"
      expect(DiscourseDiff.new(before, after).side_by_side_html).to eq(
        "<div class=\"revision-content\"><p>this is a paragraph</p></div><div class=\"revision-content\"><p>this is a paragraph</p></div>",
      )
    end

    it "adds <ins> tags around added text on the right div" do
      before = "<p>this is a paragraph</p>"
      after = "<p>this is a great paragraph</p>"
      expect(DiscourseDiff.new(before, after).side_by_side_html).to eq(
        "<div class=\"revision-content\"><p>this is a paragraph</p></div><div class=\"revision-content\"><p>this is a <ins>great </ins>paragraph</p></div>",
      )
    end

    it "adds <ins> and <del> tags on consecutive paragraphs" do
      before = "<p>this is one paragraph</p><p>here is yet another</p>"
      after = "<p>this is one great paragraph</p><p>here is another</p>"
      got = DiscourseDiff.new(before, after).side_by_side_html
      expect(got).to eq(
        "<div class=\"revision-content\"><p>this is one paragraph</p><p>here is <del>yet </del>another</p></div><div class=\"revision-content\"><p>this is one <ins>great </ins>paragraph</p><p>here is another</p></div>",
      )
    end

    it "adds <del> tags around removed text on the left div" do
      before = "<p>this is a great paragraph</p>"
      after = "<p>this is a paragraph</p>"
      expect(DiscourseDiff.new(before, after).side_by_side_html).to eq(
        "<div class=\"revision-content\"><p>this is a <del>great </del>paragraph</p></div><div class=\"revision-content\"><p>this is a paragraph</p></div>",
      )
    end

    it "adds .diff-ins class when a paragraph is added" do
      before = "<p>this is the first paragraph</p>"
      after = "<p>this is the first paragraph</p><p>this is the second paragraph</p>"
      expect(DiscourseDiff.new(before, after).side_by_side_html).to eq(
        "<div class=\"revision-content\"><p>this is the first paragraph</p></div><div class=\"revision-content\"><p>this is the first paragraph</p><p class=\"diff-ins\">this is the second paragraph</p></div>",
      )
    end

    it "adds .diff-del class when a paragraph is removed" do
      before = "<p>this is the first paragraph</p><p>this is the second paragraph</p>"
      after = "<p>this is the second paragraph</p>"
      expect(DiscourseDiff.new(before, after).side_by_side_html).to eq(
        "<div class=\"revision-content\"><p class=\"diff-del\">this is the first paragraph</p><p>this is the second paragraph</p></div><div class=\"revision-content\"><p>this is the second paragraph</p></div>",
      )
    end

    it "does not break diff on character references" do
      before = "<p>'</p>"
      after = "<p></p>"
      expect(DiscourseDiff.new(before, after).side_by_side_html).to eq(
        "<div class=\"revision-content\"><p><del>&#39;</del></p></div><div class=\"revision-content\"><p></p></div>",
      )
    end

    it "escapes attribute values" do
      before = "<p data-attr='Some \"quoted\" string'></p>"
      after = "<p data-attr='Some \"quoted\" string'></p>"
      expect(DiscourseDiff.new(before, after).side_by_side_html).to eq(
        "<div class=\"revision-content\"><p data-attr=\"Some &quot;quoted&quot; string\"></p></div><div class=\"revision-content\"><p data-attr=\"Some &quot;quoted&quot; string\"></p></div>",
      )
    end
  end

  describe "side_by_side_markdown" do
    it "returns an empty table when no content is diffed" do
      expect(DiscourseDiff.new("", "").side_by_side_markdown).to eq(
        "<table class=\"markdown\"></table>",
      )
    end

    it "properly escape html tags" do
      before = ""
      after = "<img src=\"//domain.com/image.png>\""
      expect(DiscourseDiff.new(before, after).side_by_side_markdown).to eq(
        "<table class=\"markdown\"><tr><td></td><td class=\"diff-ins\">&lt;img src=&quot;//domain.com/image.png&gt;&quot;</td></tr></table>",
      )
    end

    it "returns the diffed content on both columns when there is no difference" do
      before = after = "this is a paragraph"
      expect(DiscourseDiff.new(before, after).side_by_side_markdown).to eq(
        "<table class=\"markdown\"><tr><td>this is a paragraph</td><td>this is a paragraph</td></tr></table>",
      )
    end

    it "adds <ins> tags around added text on the second column" do
      before = "this is a paragraph"
      after = "this is a great paragraph"
      expect(DiscourseDiff.new(before, after).side_by_side_markdown).to eq(
        "<table class=\"markdown\"><tr><td class=\"diff-del\">this is a paragraph</td><td class=\"diff-ins\">this is a <ins>great </ins>paragraph</td></tr></table>",
      )
    end

    it "adds <del> tags around removed text on the first column" do
      before = "this is a great paragraph"
      after = "this is a paragraph"
      expect(DiscourseDiff.new(before, after).side_by_side_markdown).to eq(
        "<table class=\"markdown\"><tr><td class=\"diff-del\">this is a <del>great </del>paragraph</td><td class=\"diff-ins\">this is a paragraph</td></tr></table>",
      )
    end

    it "adds .diff-ins class when a paragraph is added" do
      before = "this is the first paragraph"
      after = "this is the first paragraph\nthis is the second paragraph"
      expect(DiscourseDiff.new(before, after).side_by_side_markdown).to eq(
        "<table class=\"markdown\"><tr><td class=\"diff-del\">this is the first paragraph</td><td class=\"diff-ins\">this is the first paragraph<ins>\nthis is the second paragraph</ins></td></tr></table>",
      )
    end

    it "adds .diff-del class when a paragraph is removed" do
      before = "this is the first paragraph\nthis is the second paragraph"
      after = "this is the second paragraph"
      expect(DiscourseDiff.new(before, after).side_by_side_markdown).to eq(
        "<table class=\"markdown\"><tr><td class=\"diff-del\">this is the first paragraph\n</td><td></td></tr><tr><td>this is the second paragraph</td><td>this is the second paragraph</td></tr></table>",
      )
    end
  end
end