Lapis Lazuli:Selecting an element

This page is under construction

Lapis Lazuli is an addition to Watir. This page explains how to select an element using Lapis Lazuli. Then, once you have the element selected, you can start interacting with the element. See Interacting with an element

Finding the element

There are 8 ways to find an element:

1. browser.find finds a single element matching the specifications passed to it.
2. browser.wait does the same as find, but then it waits until it's successful to find the matching specifications.
3. browser.find_all finds all elements matching the specifications passed to it.
4. browser.wait_all waits until it finds at least one matching element, but will return all of them if more were found.
5. browser.multi_find finds a single element matching one of multiple specifications passed to it. Specifications are handled in order and only the first match is returned.
6. browser.multi_wait does the same as multi_find, but then waits until it's successful to find an element.
7. browser.multi_find_all finds all elements matching one of multiple specifications passed to it. Specifications are handled in order and only elements belonging to the first match are returned.
8. browser.multi_wait_all does the same as multi_find_all, but again, it waits for at least 1 result to match the specifications.

Element selection examples

Find and wait

browser.goto 'http://training-page.testautomation.info/'

# Selecting the username input field using :objects
elm1 = browser.find(:input => {:id => 'login-username'})

# Does the same thing, also 'strings' are allowed
elm2 = browser.find('input' => {'id' => 'login-username'})

# Selecting it using a /regular expression/ (see http://rubular.com/ )
elm3 = browser.find(:input => {:id => /gin-usern/})

# Doing the same thing, but now we wait until it's present. So if it takes 5 seconds for it to show, elm1, 2 and 3 would give an error, but this one will succeed.
elm4 = browser.wait(:input => {:id => 'login-username'})

# Setting the timeout to 3 seconds, so it would throw an error after 3 seconds.
elm5 = browser.wait(:input => {:id => 'login-username'}, :timeout => 3)

# Selecting an element by providing 2 attributes
elm6 = browser.find(:input => {:id => 'login-username', :class => /form-control/})

Like selector

Like selectors are shorthands for more complex XPath-based selection. A like selector is either of:

1. A symbol, e.g. :a, in which case an XPath query is constructed for finding a elements.
2. An array of three elements, in which case an XPath query is constructed with the following components:
   1. The first is interpreted as the element name (as above),
   2. The second is interpreted as an attribute to match, and
   3. The third is interpreted as an attribute value to match.

browser.goto 'http://training-page.testautomation.info/'

# Full notation
elm1 = browser.find(:like => [
  :element => :input, 
  :attribute => :id, 
  :include => 'login-username'
])

# Short notation
elm2 = browser.find(:like => [:input, :id, 'login-username'])

# The 3rd value is "include", so you don't need to use the full ID, just a part of the text will work too.
elm3 = browser.find(:like => [:input, :id, 'gin-usern'])

# Will select the first :input field it finds present on the page
elm4 = browser.find(:like => :input)

# Also works fine with wait, or any other find alternative.
elm5 = browser.wait(:like => [:input, :id, 'login-username'])

Find all

browser.goto 'http://training-page.testautomation.info/'

# Find all input elements that are present on this page
elm1 = browser.find_all(:like => :input)
# Check how many elements were found
elm1.length
=> 2
# Select the first element [0] (zero is the first in arrays), and show the html
elm1[0].html
=> <input id="login-username" class="form-control ng-pristine ng-untouched ng-valid" ng-model="Users.login_data.name" size="60" placeholder="Username" type="text">

# Find all input elements that exist on the page (so also the ones in the background)
elm2 = browser.find_all(:like => :input, :filter_by => :exists?)
elm2.length
=> 9

Multi find

Multi find supports the use of multiple selectors and tries to find a match with any of these.

browser.goto 'http://training-page.testautomation.info/'

# Find both the username and password input field
elms = browser.multi_find_all(
  :selectors => [
    {:like => [:input, :id, 'login-username']},
    {:like => [:input, :id, 'login-password']}
  ]
)
elms.length
=> 2
elms[0].html
=> <input id="login-username" class="form-control ng-pristine ng-untouched ng-valid" ng-model="Users.login_data.name" size="60" placeholder="Username" type="text">
elms[1].html
=> <input ng-model="Users.login_data.password" class="form-control ng-pristine ng-untouched ng-valid" id="login-password" placeholder="Password" type="password">

# Find all input elements AND <a> elements that exist on the page
elms = browser.multi_find_all(
  :selectors => [
    {
      :like => :input,
      :filter_by => :exists?
    },
    {
      :like => :a,
      :filter_by => :exists?
    }
  ]
)
elms.length
=> 17
# This will print out the ID of all the elements you found.
elms.each do |e| 
  puts e.id 
end

Selection options

• Selector options, these options are part of the selector.
  • :throw - true or false weather an error should be thrown if the element can't be found.
  • :context - give a found element to search within.
  • :filter_by - the expected value is a symbol that the element responds to, e.g. :present?. If provided, only present elements (in the example) will be matched.
• General options, these options are for the whole find function
  • :message - when failing, raise a custom message.
  • :timout - Browser.wait option only, time to wait to find your selector.
  • :selectors - a list of selectors by which to find elements. Implicit when no other options are provided (see above).
  • :pick - one of the possible first parameter values to the pick_one function. Note that for find and :multi_find, the default is to pick the first element found.
  • :mode - one of match_one or match_all - determines whether the multi find functions return after finding a single element matching any _one_ of the provided selectors, or only when _all_ selectors given match at least one element.

For the default values of all the options, see Lapis Lazuli:Default values for find / multi find / find all / multi find all and wait options

Selector specific v.s. general options

In most cases, you will use both type of options in a list without separating them. But it's important to understand the difference, in case you're going to use multi_find. In multi_find you use multiple selectors, and so the notation is different.

Example of an invalid selection

browser.multi_find(
  :selectors => [
    {:like => :div},
    {:like => :input}
  ],
  :filter_by => :exists? # <-- This is the wrong place to put this, because now it's not part of the selector.
)

A correct example, where 1 selector is filtered on :exists? and another searched within a :context.

browser.multi_find(
  :selectors => [
    {:like => :div, :filter_by => :exists?},
    {:like => :input, :context => form}
  ]
)

:throw

:throw decides weather an error should be thrown when it fails to find your specifications.

browser.goto 'http://training-page.testautomation.info/'

# An error will be thrown (default is :throw => true)
browser.find(:like => [:div, :class, 'doesnotexist'])

# No error will be thrown and elm1 will result in being nil
elm1 = browser.find(:like => [:div, :class, 'doesnotexist'], :throw => false)
if elm1 == nil
  # Do something else if the element did not exist
end

:context

:context is an element you've already found, to look inside for something else.

browser.goto 'http://training-page.testautomation.info/'

# First wait for the login form container
form = browser.wait(:like => [:form, :id, 'form-login'])
# Then select the input fields inside the form
inputs = browser.find_all(
  :like => :input,
  :context => form,
  :filter_by => :exists?
)
inputs.length
=> 2
# To prove the difference without using a context
inputs = browser.find_all(
  :like => :input,
  :filter_by => :exists?
)
inputs.length
=> 9

Note that when a find/wait function become too long (2 or more options), we're putting it on multiple lines. This is to keep the code look clean and easy to read. Also a best practise to do yourself. </blockequote>

:filter_by

Possibility between :present? and :exists?

browser.goto 'http://training-page.testautomation.info/'

# Then select the input fields inside the form
inputs = browser.find_all(
  :like => :input,
  :context => form,
  :filter_by => :exists?
)
inputs.length
=> 2
# To prove the difference without using a context
inputs = browser.find_all(
  :like => :input,
  :filter_by => :exists?
)
inputs.length
=> 9

In addition, a helper function is exposed that allows you to pick an element from a collection (array) of elements.

Picking an Element

The pick_one helper function is easily explained in isolation, but it should be noted that it also underlies the find and multi_find functions:

browser.pick_one(:first, collection)  # returns the first item from the collection
browser.pick_one(:last, collection)   # returns the last item from the collection
browser.pick_one(:random, collection) # returns a random item from the collection
browser.pick_one(12, collection)      # returns the 12th item from the collection

You should not usually need to use this function directly, but instead use one of the find functions.

Find Function Syntax

All find functions accept much the same parameters; the general syntax is this:

browser.find(selector1)
browser.find(:some_option => value, :selectors => [selector1])

# browser.find_all same as browser.find

browser.multi_find(selector1, selector2, ...)
browser.multi_find(:some_option => value, :selectors => [selector1, selector2, ...])

# browser.multi_find_all same as browser.multi_find

This syntax affords the flexibility of providing options to the functions, without forcing you to provide any.

Find Options

The following options are interpreted by all find functions:

• :selectors - a list of selectors by which to find elements. Implicit when no other options are provided (see above).
• :pick - one of the possible first parameter values to the pick_one function. Note that for find and :multi_find, the default is to pick the first element found.
• :mode - one of match_one or match_all - determines whether the multi find functions return after finding a single element matching any _one_ of the provided selectors, or only when _all_ selectors given match at least one element.
• :filter_by - the expected value is a symbol that the element responds to, e.g. :present?. If provided, only present elements (in the example) will be matched.
• :context - give a found element to search within.
• :message - when failing, raise a custom message.

Selectors

Selectors can be the kind of selectors that would be passed to the Watir browser's functions, but LapisLazuli affors far greater flexibility here.

1. If a selector is a string, e.g. "a", then elements with the symbol name are found, using Watir's built-in functions.
2. If a selector is a symbol, e.g. :a, then elements with the symbol name are found, but using XPath instead.
3. If a selector is a hash, it is considered to be a regular Watir selector, e.g. :id => /some-id/.
   1. If this hash contains a :like key, the value of this key is further interpreted before passing the entire hash on to Watir (see below).
   2. If this hash contains a :context key, the value of this key is expected to be a Watir element, and a search will be performed relative to this element. If the context is not provided, the search starts at the document root.

Like Selectors

Like selectors are shorthands for more complex XPath-based selection. A like selector is either of:

1. A symbol, e.g. :a, in which case an XPath query is constructed for finding a elements.
2. An array of three elements, in which case an XPath query is constructed with the following components:
   1. The first is interpreted as the element name (as above),
   2. The second is interpreted as an attribute to match, and
   3. The third is interpreted as an attribute value to match.

Note that like selectors **add** to a regular Watir selector. It's perfectly legitimate to use regular selectors and like selectors in combination, but the result may be unexpected.

Examples

# Find any link. same as browser.a
browser.find(:a)                      
browser.find({:like => :a}) # xpath


# same as browser.a(:href => /test/)
browser.find(:a => {:href => /test/})

# More complicated version:
browser.find(
  {:a => {:class => "loginButton"}}, 
  {:a => {:href => /login/}},
  {:button => {:name => "login"}}
)

# Find element where an attribute contains something. 
# Uses XPath instead of the slower regexes:
# browser.a(:href => /account\/login/)
browser.find(:like => {
    :element => :a, 
    :attribute => :href, 
    :include => "account/login"
})

# A shorthand
browser.find(:like => [:a, :href, "account/login"])

# Finding a single class is also possible if you add spaces around it
browser.find(:like => [:a, :class, " login "])

# And also support for XPath text
browser.find(:like => {
    :element => :a, 
    :attribute => :text, 
    :include => "Login"
})

# Finding based on name, id or text
browser.find("login")

# Finding an element within another element
form = browser.find("register_form")
firstname_field = browser.find(
    :input => {:name => 'firstname'},
    :context => form
)