It happens to me quite often (I think after switching to an external screen but maybe that's not the only time) that the emacs window/frame will become stuck and I'm not able to resize it in a meaningful way. That is the usual shortcuts (I use https://rectangleapp.com/) don't work to move the window or resize it and also resizing with mouse behaves very strangly; maximizing the window leads to a broken state where bunch of the screen is just dark. The only thing that helps is to restart the emacs. Anybody else experiencing this problem? Is there a way to fix this? Btw. I'm using spacemacs.

What's your preferred testing package/lib for Emacs Lisp, and why?