Tag Archives: anti-patterns

Five page object anti-patterns

I’ve observed some page object anti-patterns which commonly arise when starting out designing end-to-end automated tests. Chris McMahon recently asked for some feedback on his initial test spike for Wikipedia, and some of these anti-patterns were present.

Anti-pattern one: frequently opening and closing browsers

I often see both RSpec and Cucumber tests frequently opening and closing browsers. This slows down test execution times, and should be avoided unless absolutely necessary.

You can clear cookies between tests if you’re worried about state.

To open and close the browser only once in Cucumber, specify this in your env.rb file:

browser = Watir::Browser.new

Before do
  @browser = browser

at_exit do

To open and close the browser only once in RSpec:

browser = Watir::Browser.new

RSpec.configure do |config|
  config.before(:each) { @browser = browser }
  config.after(:suite) { browser.close }

Anti-pattern two: hard coding URLs on page classes

Chances are you’ll at some point run your automated tests in different environments, even if it’s just to verify that production has been updated correctly. If you’ve hard coded URLs in page classes, this can be problematic.

Fortunately it’s easy to avoid, by creating a module that contains base URLs which can be accessed by page classes. These base URLs can be stored in YAML files which can be switched for different environments.

module Wikipedia
  BASE_URL = 'https://en.wikipedia.org'

class BogusPage
  include PageObject
  page_url "#{Wikipedia::BASE_URL}/wiki/Bogus_page"

Anti-pattern three: pages stored as instance variables in steps or rspec specs

I don’t like seeing pages stored as instance variables (those starting with an @) in Cucumber steps or RSpec specs, as it introduces state and thus more room for error.

If you’re using the page-object gem, there are two methods available to access pages directly without using instance variables: visit_page and on_page (also visit or on from 0.6.4+). Both of these can be used as blocks, so you can perform multiple actions within these methods.

visit LoginPage do |page|
  page.login_with('foo', 'badpass')
  page.text.should include "Login error"
  page.text.should include "Secure your account"

Anti-pattern four: checking the entire page contains some text somewhere

I often see people checking that the entire web page contains some expected text. Even if the text was at the very bottom of the page hidden in the footer the test would probably pass.

You should check the text is where it should be, using a container that it should belong to. Ideally a span or a div may exist that contains the exact text, but even if it’s in a slightly larger container it is still better than asserting it exists somewhere on the page.

class BogusPage
  include PageObject
  cell :main_text, :class => 'mbox-text'

visit_page BogusPage do |page|
  page.main_text.should include 'Wikipedia does not have an article with this exact name'
  page.main_text.should include 'Other reasons this message may be displayed'

Anti-pattern five: using RSpec for end-to-end tests

This one is contentious, and I am sure I’ll get lots of opinions to the contrary, but I believe that RSpec is best suited to unit/integration tests, and Cucumber is suited to end-to-end tests.

I find I create duplication when trying to do end-to-end tests in RSpec, which is where Cucumber step definitions come in. Trying to do unit tests in Cucumber seems like too much overhead, and in my opinion is more suited to RSpec.