My onOpen for showing custom menu in google sheet scripts is working perfectly and I have also done onInstall simply like this
function onInstall(e){
onOpen(e)
}
onOpen is running under all oath types but then google give this error when I try to publish addon
Menu - Menu options not shown after App is installed. Please ensure that the add-on correctly uses onInstall() and onOpen() to populate its menu. The menu items populate when the add-on is first installed and when a different file is opened. See Editor add-on authorization.
So I don't understand this problem also if anyone know how to mock onInstall please let me know.
I tried running test deployment but cannot mock onInstall in it.
Found the solution as Daniel mentioned.
First private deploy and test the extention then it should work when extention will be deployed publically. Otherwise we can't test onInstall.