Idea was as follows:
The regular JavaScript click test verifies that click has been made using JavaScript. Since the CssDriverTest extends the JavaScriptDriverTest, then it also extends test scope and not only verifies that via JavaScript (parent method call) but also via CSS (extended method call). As a side benefit the CSS test won't be reached if JS test (parent method call) fails.

Does such test union make more sense now to keep it as is?