Merge branch 'docs-qa-dynamic-element-validation' into 'master'

Documentation for dynamic element validation

See merge request gitlab-org/gitlab-ce!29169

doc/development/testing_guide/end_to_end/dynamic_element_validation.md

+# Dynamic Element Validation
+
+We devised a solution to solve common test automation problems such as the dreaded `NoSuchElementException`.
+
+Other problems that dynamic element validations solve are...
+
+- When we perform an action with the mouse, we expect something to occur.
+- When our test is navigating to (or from) a page, we ensure that we are on the page we expect before 
+test continuation.
+
+## How it works
+
+We interpret user actions on the page to have some sort of effect. These actions are
+
+- [Navigation](#navigation)
+- [Clicks](#clicks)
+
+### Navigation
+
+When a page is navigated to, there are elements that will always appear on the page unconditionally.
+
+Dynamic element validation is instituted when using 
+
+```ruby
+Runtime::Browser.visit(:gitlab, Some::Page)
+```
+
+### Clicks
+
+When we perform a click within our tests, we expect something to occur.  That something could be a component to now 
+appear on the webpage, or the test to navigate away from the page entirely.
+
+Dynamic element validation is instituted when using
+
+```ruby
+click_element :my_element, Some::Page
+```
+
+### Required Elements
+
+#### Definition
+
+First it is important to define what a "required element" is.
+
+Simply put, a required element is a visible HTML element that appears on a UI component without any user input.
+
+"Visible" can be defined as
+
+- Not having any CSS preventing its display. E.g.: `display: none` or `width: 0px; height: 0px;`
+- Being able to be interacted with by the user
+
+"UI component" can be defined as
+
+- Anything the user sees
+- A button, a text field
+- A layer that sits atop the page
+
+#### Application
+
+Requiring elements is very easy.  By adding `required: true` as a parameter to an `element`, you've now made it
+a requirement that the element appear on the page upon navigation.
+
+## Examples
+
+Given ...
+
+```ruby
+class MyPage < Page::Base
+  view 'app/views/view.html.haml' do
+    element :my_element, required: true
+    element :another_element, required: true
+    element :conditional_element
+  end
+  
+  def open_layer
+    click_element :my_element, Layer::MyLayer
+  end
+end
+
+class Layer < Page::Component
+  view 'app/views/mylayer/layer.html.haml' do
+    element :message_content, required: true
+  end
+end
+```
+
+### Navigating
+
+Given the [source](#examples) ...
+
+```ruby
+Runtime::Browser.visit(:gitlab, Page::MyPage)
+
+execute_stuff
+```
+
+will invoke GitLab QA to scan `MyPage` for `my_element` and `another_element` to be on the page before continuing to
+`execute_stuff` 
+
+### Clicking
+
+Given the [source](#examples) ...
+
+```ruby
+def open_layer
+  click_element :my_element, Layer::MyLayer
+end
+```
+
+will invoke GitLab QA to ensure that `message_content` appears on
+the Layer upon clicking `my_element`.
+
+This will imply that the Layer is indeed rendered before we continue our test.

doc/development/testing_guide/end_to_end/page_objects.md

@@ -83,14 +83,16 @@ module Page
 
       # ...
     end 
+  end
 end
 ```
 
-The `view` DSL method declares the filename of the view where an
-`element` is implemented.
+### Defining Elements
+
+The `view` DSL method will correspond to the rails View, partial, or vue component that renders the elements.
 
 The `element` DSL method in turn declares an element for which a corresponding
-`qa-element-name-dasherized` CSS class need to be added to the view file.
+`qa-element-name-dasherized` CSS class will need to be added to the view file.
 
 You can also define a value (String or Regexp) to match to the actual view
 code but **this is deprecated** in favor of the above method for two reasons:
@@ -115,6 +117,37 @@ view 'app/views/my/view.html.haml' do
 end
 ```
 
+### Adding Elements to a View
+
+Given the following elements...
+
+```ruby
+view 'app/views/my/view.html.haml' do
+  element :login_field
+  element :password_field
+  element :sign_in_button
+end
+```
+
+To add these elements to the view, you must change the rails View, partial, or vue component by adding a `qa-element-descriptor` class
+for each element defined.
+
+In our case, `qa-login-field`, `qa-password-field` and `qa-sign-in-button`
+
+**app/views/my/view.html.haml**  
+
+```haml
+= f.text_field :login, class: "form-control top qa-login-field", autofocus: "autofocus", autocapitalize: "off", autocorrect: "off", required: true, title: "This field is required."
+= f.password_field :password, class: "form-control bottom qa-password-field", required: true, title: "This field is required."
+= f.submit "Sign in", class: "btn btn-success qa-sign-in-button"
+```
+
+Things to note:
+
+- The CSS class must be `kebab-cased` (separated with hyphens "`-`")
+- If the element appears on the page unconditionally, add `required: true` to the element. See
+[Dynamic element validation](dynamic_element_validation.md)
+
 ## Running the test locally
 
 During development, you can run the `qa:selectors` test by running