Add an extension point for optional wait operation before TriggerAfterPageChangeEventAsync is called (OSOE-972)

[sarahelsaig]

Sometimes frontend code immediately triggers an asynchronous fetch to get data after the page has loaded. One example is Lombiq.DataTables, where the data is delivered through a separate JSON-returning web request. To achieve the correct, repeatable behavior post-navigation events such as html-validate and Axe checks should only be called when this secondary loading has finished, so a page with useful content can be evaluated.

Unfortunately, there is no universal way to tell when is a site ready, so you'd want to write specific wait logic for each test that accommodates the frontend technologies used in that specific test. We should add some property to the configuration property (e.g. context.Configuration.Events.WaitAfterPageChange : Func<UITestContext, Task>) which can wait for the page state to indicate no loading.

Also implement such a wait for Lombiq.OSOCE.Tests.UI.Tests.ModuleTests.BehaviorDataTablesTests.RecipeDataShouldBeDisplayedCorrectly.

For more context see in Jira.

Jira issue