govuk-diff-pages

This app provides a set of rake tasks that produce diffs of the staging and production GOV.UK websites. Diffs are provided in 3 distinct forms:

• Visual
  • Screenshots of pages in each environment, compared and presented in an HTML gallery for viewing in a browser.
• HTML
  • Diffs of the markup on each page, also presented in gallery form.
• Text
  • Diffs of text content on each page, with the results sent to STDOUT.

These use a fork of the BBC's wraith gem (https://github.com/alphagov/wraith). The fork adds two extra configuration variables, allowing the user to specify the number of threads to use, and the maximum timeout when loading pages.

The rake task expects an env var URI to be set - this should be the location of a YAML file containing a list of GOV.UK paths to run the diff against. See spec/fixtures/test_paths.yaml for an example.

bundle exec rake diff:visual URI=https://uri/to/a/yaml/file.yaml

Results are written to $PROJECT_ROOT/results/visual/gallery.html.

The following are required in order to run a visual diff. A pre-flight check for these dependencies runs when you execute the diff:visual task.

• ImageMagick
• phantomjs - preferrably 1.9 rather than 2.0

These use Diffy gem (https://github.com/samg/diffy) as the underlying diff library.

Expects URI to be set, as with Visual Diffs.

bundle exec rake diff:html URI=https://uri/to/a/yaml/file.yaml

Results are written to $PROJECT_ROOT/results/html/gallery.html.

These also use Diffy gem.

bundle exec rake diff:text pages.yml

Where pages.yml is a YAML array of paths to compare. For example:

- government/organisations/prime-ministers-office-10-downing-street
- government/topical-events/budget-2016
- topic/competition/regulatory-appeals-references

Text diffs can also specify the domains to compare using the LEFT and RIGHT environment variables. Defaulting to our www-origin.staging and www-origin.publishing domains respectively.

Plain-text diffing can be parallelised by starting multiple processes with individual page files.

bundle exec rspec

MIT License