Refactor the wait and the page-loading handling

[helkv]

When a new page is loaded and after certain actions the test-execution has to wait until all needed web-elements are present in the DOM. Sometimes a loading screen (.loaderWrapper) is displayed.

Actual Approach:

• a globally set implicit wait time
• many explicit waits in the page object classes to wait for single web-elements to be visible/clickable/...
• some Thread.sleep()
• some explicit waits in the page object classes to wait for the loading screen to disappear

Problems:

• implicit and explicit waits should not be mixed
• unnecessary explicit waits
  -> waits for certain elements which are not used afterwards (often used for a general approach, to check weather the new page is loaded and new actions can be executed on its elements)
• Thread.sleep() should not be used in the tests
• explicit waits for the loading screen only exist at certain points with long loading times
  -> no generic approach

TODO:

• keep the explicit waits where useful and required
• remove the implicit wait time if possible
• replace Thread.sleep() with explicit waits (see also Replace Thread.sleep() calls with explicit waits #30)
• use a more generic approach to handle the wait for the loading screen
  -> always wait for the loading screen if it is activated

[helkv]

General Waiting-Approaches proofed to be successful:

1. Wait directly after a Selenium action for something to be loaded
   • Wait until an element is no longer attached to the DOM:
     WebElement elementToBecomeStale = driver.findelement(...);
buttonElement.click()
wait.until(ExpectedConditions.stalenessOf(elementToBecomeStale));
   • This can be appended by checking the loading status of the page (after the staleness-wait):
     wait.until(webDriver -> ((JavascriptExecutor) webDriver).executeScript("return document.readyState").equals("complete"));
2. Wait directly before a Selenium action for the element to be available
   • Wait until the element is visible
     wait.until(ExpectedConditions.elementToBeClickable(element));
   • Wait until the element is clickable
     wait.until(ExpectedConditions.visibilityOf(element));