PageObject testing automation pattern

1. PageObject
testing automation pattern
Pavel Mitin . 2014

2. Real life example
When /^user clicks on Action>>"(.*)" in the book list$/ do |action_name|
book_name_column = column_index "//table[@id='list-table']", 'Name'
@book = first(:xpath,"//table/tbody/tr/td[#{book_name_column}]//a").text
action_column = column_index "//table[@id='list-table']", 'Action'
first(:xpath, "//table/tbody/tr/td[#{action_column}]//a[contains(.,'Action')]").click
first(:xpath, "//table/tbody/tr/td[#{action_column}]//ul/li/a[contains(.,'#{action_name}')]").click
end

3. Problem
When /^user clicks on Action>>"(.*)" in the book list$/ do |action_name|
book_name_column = column_index "//table[@id='list-table']", 'Name'
@book = first(:xpath,"//table/tbody/tr/td[#{book_name_column}]//a").text
action_column = column_index "//table[@id='list-table']", 'Action'
first(:xpath, "//table/tbody/tr/td[#{action_column}]//a[contains(.,'Action')]").click
first(:xpath, "//table/tbody/tr/td[#{action_column}]//ul/li/a[contains(.,'#{action_name}')]").click
end
WHAT vs HOW

4. Be more OO
All problems in computer science can be
solved by another level of indirection
Butler Lampson/David Wheeler

5. PageObject pattern
* HOW becomes the internal implementation details
* WHAT manifests itself in public interface

6. Code example
book_list = BookListPanel.new
...
book_list.filter_by_author author
...
book_list.paginate 2

7. Code example
book_list = BookListPanel.new
...
book_list.filter_by_author author
...
book_list.paginate 2
Object-oriented
wrappers
around UI pieces

8. OLD

9. NEW

10. PageObject vs PanelObject
There's an argument here that the name "page object" is
misleading because it makes you think you should have just one
page object per page. Something like "panel object" would be
better - but the term "page object" is what's become accepted.
Another illustration of why naming is one of the TwoHardThings.
Martin Fowler

11. PageObject vs PanelObject
Options:
1) Single object per page
2) Tree of objects (page object + panel objects)
3) Independent panel object(s)

12. PageObject vs PanelObject
Options:
1) Single object per page
2) Tree of objects (page object -- root)
3) Independent panel object(s)
Good object

13. PageObject vs PanelObject
Options:
1) Single object per page
2) Tree of objects (page object -- root)
3) Independent panel object(s) Still over-complicated
Can reveal hierarchy of
complex UI

14. PageObject vs PanelObject
Options:
1) Single object per page
2) Tree of objects (page object -- root)
3) Independent panel object(s)
Simple and flexible

15. More examples
# https://github.com/ngauthier/domino
class Dom::Post < Domino
selector '#posts .post'
attribute :title
attribute :body, '.post-body'
attribute :posted_at { |text| Date.parse text }
end

16. More examples
# https://github.com/ngauthier/domino
assert_equal 4, Dom::Post.count
refute_nil Dom::Post.find_by_title('First Post')

17. More examples
# https://github.com/ngauthier/domino
def delete
within(id) { click_button 'Delete' }
end
…
refute_nil Dom::Post.find_by_title('First Post')
Dom::Post.find_by_title('First Post').delete

18. Asserts
Can PageObject class contain asserts?

19. Asserts
# External assert
assert book_list.empty?
# vs
# Internal assert
book_list.assert_emtpy

20. Asserts
# Internal approach works well with
# complex asserts
book_list.assert_searchable
# 1. Put a term in the search input
# 2. Hit “Search”
# 3. Check each item contains the term

21. Asserts
# Mixins / traits etc.
book_list = BookListPanel.new
book_list.extend ListAsserts
...
book_list.assert_searchable

22. Chain of pages
# Don't try this at home ;)
books = book_form.submit
assert 1, books.size
book = books.first.show_details

23. WEB only?
No

24. No silver bullet
You have to maintain the layer of abstraction.

25. No silver bullet
Don’t use if your interface is not uniform.

26. Sweet spot

27. DRY it
# production code (UI widget in view layer)
books = Widget::BookList.new current_user
books.render
# test code (UI widget + page object)
books = Widget::BookList.new current_user
books_panel = BookListPanel.new books

28. Thanks
@map_and_filter
http://novembermeeting.blogspot.com