We develop office-js based addin for Excel and we've come to a place where we want to write automated functional tests (preferably with Selenium) for desktop version of Excel on Windows.
First issue we've encountered was that different combinations of Excel/Windows use either IE/Edge's webview underneath. Let's let IE die and assume we just need to test with Edge webview (EdgeHTML, as Edge-chromium webview is not yet released).
So the main issue is: we cannot (or don't know how to) connect addin's webview with Selenium, because we're not responsible for launching webview's process - it's launched by Excel itself. Is there any recommended way to run functional tests for desktop version of Excel with addin inside? We can control Excel itself through COM, so that's not an issue. But how to control the webview underneath addin?
We've tried WinAppDriver, but it gives windows-specific XML of generated window, not addin's HTML we'd like to see, making navigation and assertions fragile and complicated.
I think we searched just everywhere and couldn't find any pretty solution, so dirty hacks are also allowed, as long as they will work reliably and not too slow.