Right now, most of the RevisionSlider Selenium tests are written in Ruby. However, it was decided to use Node.js for selenium tests.
This still needs to be done for the remaining RevisionSlider Ruby tests. The basic setup for the Node.js tests is already there and was added in 499855
See T180246: Port ElectronPdfService Selenium tests from Ruby to Node.js for an example where the tests were already ported
See subtasks of this ticket that reflect the features that need to be ported.