So instead of

       boolean needToUninstall() {
         if now > EXPIRATION_TIME
           return true
         else
           return false
       }

we need to

       boolean needToUninstall(givenTime) {
         if givenTime > EXPIRATION_TIME
           return true
         else
           return false
       }
       
       needToUninstall(now) && doUninstall()

so the code is now testable. Or simply use dependency injection to change the value of `now`

Is it hard to pass time as parameter?