Testing web front ends is a pain, partly because we end up testing the back end with them. Selenium helps by automating the input, but the selenium driver code lacks high-level interfaces for things like "find_and_click" or "find_and_key". Adding these with a wrapper makes data-driven selenium testing via Object::Exercise easy.

1. Selenium Sandwich Part 1:
Automating Selenium Sequences
Steven Lembark
Workhorse Computing
lembark@wrkhors.com

2. Testing web front ends is different
Much of the testing is manual.
Tests validate multiple systems at once.
Often cannot test without a running back end.
Here is the first installment of a better way.

3. Been there?
Hey where did that come from? Check the
logs...
Can't use that database: dropped it last
week...
Server isn't using your version any more...

4. Q: Why is it this bad?
A: Because you aren't testing the front end.

5. Q: Why is it this bad?
A: Because you aren't testing the front end.
Q: Where do you get the content for testing?

6. Q: Why is it this bad?
A: Because you aren't testing the front end.
Q: Where do you get the content for testing?
A: The back end.

7. Q: Why is it this bad?
A: Because you aren't testing the front end.
Q: Where do you get the content for testing?
A: The back end.
You are testing both ends at once.

8. Q: Why is it this bad?
A: Because you aren't testing the front end.
Q: Where do you get the content for testing?
A: The back end.
You are testing both ends at once.
That makes front ends different.

9. Testing just the front end
Isolation and repeatiblity are key to testing.
Selenium helps with repeatability.
Catch: Hardwired code required for each test.

10. Example Selenium::Driver code

11. Q: Is there a better way?
A: Data driven code.
With Object::Exercise code like:
$object->method( @argz )->...
Becomes
[ $method => @argz ], ...

12. Daisy-chain logic
find_element returns an object:
$driver->find_element( ... )->click;
$driver
->find_element( ... )
->send_keys( ... )
->send_keys( KEY->{ enter } );

13. False Lazyness
Calls to “find_element” use the element.
Hardwiring multiple calls is extra work.
Why not “find_and_click”, “find_and_type”?
A: Selenium interface doesn't declare them.
Q: Why can't we do better than the interface?

14. True Lazyness
Adding high-level abstractions is easy.
Wrap the object.
Add an AUTOLOAD.
Redispatch low-level calls.

15. Selenium::Easy
What would you use for a wrapper object?

16. Selenium::Easy
What would you use for a wrapper object?
Usual suggestion:
{ wrapped => $object }

17. Selenium::Easy
What would you use for a wrapper object?
Usual suggestion:
{ wrapped => $object }
Downsides: Bulky, Slow, Klutzy->{ syntax }

18. Simpler wrapper
sub construct
{
my $proto = shift;
bless
( my $obj = '' ),
blessed $proto || $proto
}

19. Simpler packaging
sub initialize
{
state $pkg
= 'Remote::Selenium::Driver';
my $wrapper = shift;
$$wrapper = $pkg->new( @_ );
$wrapper
}

20. High-level methods
sub find_and_key
{
my ( $wrapper, $find ) = splice @_,0,2;
my $found
= $$wrapper->find_element( @$find );
$found->send_key( $_ )
for @_, KEYS->{ enter };
}
High-level methods

21. Dispatching low-level methods
our $AUTOLOAD = '';
AUTOLOAD
{
my $wrapper = shift;
my $i = 1 + rindex $AUTOLOAD, ':';
my $name = substr $AUTOLOAD, $i;
$$wrapper->$name( @_ )
}

22. Q: Why not just drive a new class?
A: Avoid knowing base class structure.
AUTOLOAD and $$wrapper
have no idea what the wrapped object is.

23. Replacing custom code
Daisy chains now become single-steps:
$wrapper->find_and_key( ... );
$wrapper->find_and_click( ... );

24. Replacing custom code
Passed to Object::Exercise as:
$wrapper->$exercise
(
[ [ find_and_key => ... ], ... ],
[ [ find_and_click => ... ], ... ],
);

25. Replacing custom code
Or with YAML like:
---
-
- - find_and_key
- ...
-
- - find_and_click
- ...

26. Data-driven equivalent
# use Object::Exercise;
# $wrapper->$exercise( $yaml );
---
-
# verbose speicfic to "prepare_test" block.
# prepare test ignores return values.
- verbose
- - prepare_test
- - set_implicit_wait_timeout
- 50000
- - get
- http://www.google.com
-
- - find_send_keys
- - q
- name
- YAPC Salt Lake City
-
- - find_click
- '#rso li h3 a'
- css

27. Data-driven equivalent
-
- regex
- - get_title
- YAPC
- Title includes 'YAPC'
-
- - find_click
- Talks and Schedule
-
- - find_click
- Schedule
-
- - find_click
- Wednesday
-
- - find_click
- Selenium
- partial_link_text
-
- regex
- - get_title
- Selenium
- Title includes 'Selenium'

28. So ends our first episode...
Developing wrapper classes in Perl is trivial.
Repeatable test metadata is simple enough:
Use high-level calls with Selenium.
Coming up next: Isolating the front end.

29. =head1 SEE ALSO
Good general talk on Selenium.
Introduces the Selenium Playground on
github:
<http://www.slidesearchengine.com/slide/
testing-your-website-with-selenium-perl>

30. =head1 SEE ALSO
Overview of Object::Exercise
<http://www.slideshare.net/lembark/object-
exercise?qid=6ed2ecf1-2520-4d4a-b6fa-
545b95693ebc&v=qf1&b=&from_search=1>
Current documentation:
<http://search.cpan.org/~lembark/Object-
Exercise-3.02/lib/Object/Exercise.pm>