Spectre

Spectre is a web application to diff screenshots. It's heavily influence by VisualReview, BackstopJS and Wraith.

Requirements

• Postgres
• Imagemagick

Setup

• Clone the repo
• bundle exec rake db:create && bundle exec rake db:schema:load
• bundle exec rails s
• Copy .env.example and rename to .env. Change the url details if you need to.

Submitting tests

A "test" is a screenshot and associated metadata. A test is categorised under a Project, which in turn has (test) Suites. A test is submitted and associated with a "run" of a suite.

First you should create a new "run". The JSON response will contain the run_id to submit with each subsequent test.

POST /runs
  project: My Projetc Name
  suite: My Suite Name

Then you can submit a screenshot!

POST /tests
  test:
    run_id: {run_id from above},
    name: Homepage,
    platform: OSX,
    browser: PhantomJS,
    width: 1024,
    screenshot: <File>

• name is a friendly name of your test. It should describe the template, component or state of the thing you've screenshotted
• platform is the OS/platform that the screenshot was taken on (e.g. OSX, Windows, iOS, Android etc.)
• browser is the browser that was used to render the screenshot. This will usually be a headless webkit such as Phantom, but if using Selenium you may have used a "real" browser
• width is the screenshot size
• screenshot is the image itself. PNGs are preferred

Dummy tests

An example test run can be executed using:

bundle exec rake screenshots

Administration

Spectre doesn't provide a UI or API to edit or delete content. We've included rails_admin, so head to /admin for this. By default there is no password.

TODO

• refactor to remove code from fat controllers
• ability to get a canonical link to the baseline screenshot for a named test (e.g. ability to hotlink a screenshot into a component library)
• test coverage is currently nil
• upgrade to Rails 5 when released
• use ActionCable on Run::show view to update list as tests are submitted
• disable a test if it fails more than n times (see below)
• ability to set the "fuzz" factor on a per-test basis that overrides the default. e.g. the stat component antialiasing (http://spectre.tools.fridayengineering.net/projects/hsbc-cmb-pws/suites/components/runs/10?name=statistic&browser=&platform=&size=375&result=Failed)
• refactor "width" property of a test to be more generic "size" so that it can support form factor e.g. "mobile", "tablet". won't always be a numeric width
• mark a test as passed when it's set as a baseline

Disabling a test if it fails more than N times

Occassionaly we get a repo that has nightly tests that fail repeatedly for more than a week. In this instance we keep collecting screenshots (because we keep screenshots for failed tests). It'd be useful to be able to disable a job from within Spectre, either:

• disable a project so that new runs cannot be created
• configure a threshhold after which each individual tests are disabled, to reduce noise. Or auto-disable a project if there are consistent failures on every run? Would need a way to re-enable them.