One of the primary objectives during recording in Coded UI Test is to generate a robust search condition for a UI control to be uniquely identifiable during playback. In this post I’ll mention some of the search logic specific to the Silverlight UI Automation support within Coded UI Test introduced in the VS 2010 Feature Pack 2.

Search condition generation during Recording

 

For Silverlight control, Coded UI Test relies primarily on the Automation properties of the control. The sequence of looking for a search property in order descending of priority is

AutomationId,

Name,

LabeledBy,

HelpText,

AccessKey,

AcceleratorKey

Specific controls support additional searchable properties. For instance, Button supports  “DisplayText”, Image supports “Source”, DataGrid Cell supports “ColumnIndex” searchable property and likewise. The various search configurations mentioned here are applicable to Silverlight control search too (except for the SearchConfiguration.VisibleOnly configuration).

 

For a Silverlight object hosted in IE, the search hierarchy will consist of an IE search part and Silverlight search part –

 

Top Level Window à {IE Search Hierarchy} à Silverlight Root Visual Element à Parent of Target Element à Target Element.

 

Additional hierarchy can be generated in between the Parent and Silverlight Root Visual element based on the specific control requirement. For example, certain controls such as Datagrid, Tree, TreeItem, Tab, List Item are, at almost all times, included in the search hierarchy if they are found in the ancestor hierarchy of the target element. As an example, the extended search hierarchy of a DataGrid Cell will show up as something like

 

TopLevelWindow à {IE Search Hierarchy} à Root Visual Element (Silverlight) à DataGridTable (Silverlight) à DataGridRow(Silverlight) à DataGridCell (Silverlight)

 

 

Search path during Playback

 

The overall search logic remains identical to what is followed in other UI technologies. It is a breadth first search wherein the top level window is first searched and used as a container for searching the next control in the search condition hierarchy. This is done recursively until the leaf control in the search hierarchy is found.

 

As an example, for a simple button inside a Silverlight page, the search hierarchy will be typically of the format –

 

TopLevelWindow à Document (IE BODY Tag) à Pane (IE DIV Tag) à Custom (IE OBJECT Tag) à Root Visual Element (Silverlight) à Button (Silverlight).

 

For the top-down search till the IE Object Tag, the existing search features and settings in Coded UI Test are applicable. Once the search switches to the Silverlight technology (i.e. Root Visual element of the Silverlight page), there are few limitations to the search.

 

 

What is missing currently in Silverlight control search?

 

1.    Playback.PlaybackSettings.ShouldSearchFailFast

      This setting is not honored currently. However, there is some level of customization that can be done using the Playback.PlaybackSettings.SearchTimeout and the Playback.PlaybackSettings.WaitForReadyTimeout settings to tweak the timeout at which the search should abort. The later may not seem obvious, and is hence explained in more detail in a section below.

 

2.    Playback.PlaybackSettings.MatchExactHierarchy

Silverlight control search does not currently honor  MatchExactHierarchy = false. So, the search condition specified for the entire Silverlight hierarchy needs to be accurate for the search to succeed. In the above example, it is the Root Visual Element and the Button control.

 

3.     Playback.PlaybackSettings.SmartMatchOptions

      Control level smart match is not currently supported i.e. SmartMatchOptions.Control

Note that Regex match is not yet supported in Coded UI Test. So the only option available is to specify the PropertyExpressionOperator.Contains condition operator in the search properties.

For example, if the button’s name is of format “Submit<SomeDynamicId>”, the search property can be defined as –

uISubmitButton.SearchProperties.Add("Name", "Submit", PropertyExpressionOperator.Contains);

 

4.     There is no concept of FilterProperties as supported in Web Technology in Coded UI Test.

 

 

How to handle search failures because of slow page loading?

 

If the XAP download takes a huge amount of time to load, the search during playback would fail since the Silverlight controls will not have been rendered in the visual tree. The internal search algorithm uses a wait and retry logic to search for a control while checking the visual tree rendering status at each wait interval (this time interval is upped exponentially on each iteration). I will not be explaining the details here, but the important thing to note is that if there is no rendering happening within a polling interval, the search will return with failure status. This polling interval is currently set to half of the Playback.PlaybackSettings.WaitForReadyTimeout which has a default value of 60 seconds (i.e. the default polling interval is 30 seconds). So to tackle slow page loading time, you can configure this Playback.PlaybackSettings.WaitForReadyTimeout to a desired value.

Note: Playback.PlaybackSettings.WaitForReadyTimeout does affect the normal search failure time in scenarios where there is some visual rendering happening in the Silverlight page. So you would need to strike an appropriate balance based on the type of application you are testing.