First of all -R means you are attempting to resume an existing screen session that probably already runs something. In that case you can't just push your shell commands into it and hope they will be executed. What if the resumed screen session had for example an editor running? So, don't use -R when you want to specify a command to run.
The other problem is that once you use input redirection through
<< __EOF__ the called program runs without a tty, i.e. without an interactive terminal. That can be easily demonstrated here:
$ tty << __EOF__
not a tty
Fortunately for you
screen has a support for running custom commands upon launch. It's as simple as
screen command args (notice no -R in after screen).
In your case you'll have to pass all your commands as arguments to
/bin/sh because screen won't run multiple shell commands for you. Something like this should work:
$ screen /bin/sh -cx "cd /home/users/devops_tester/apps/Selenium-Webdriver; export DISPLAY=:99; npm start"
It will spawn a new screen session and run your commands. The -x makes shell print the commands it runs for your reference. It's optional, you can remove it.
You can also run the above in an immediately detached screen session and re-attach to it later:
$ screen -d -m /bin/sh -cx "cd /home/...; export ...; npm start"
# runs the commands in screen but returns immediately
That's useful if you want to run the commands during system startup for instance.
And of course you can re-attach the above session to see what's going on there.
$ screen -R # re-attach to the above screen session
Last but not least - instead of passing all your commands as arguments to
/bin/sh it may be easier to create a little 3-liner shell script, make it executable and run that with a simple call:
$ screen /path/to/the-script