Isn't it already covered firmware_ECWakeSource?

logging.info("Suspend and wake by power button.")
self.switcher.mode_aware_reboot(
        'custom',
        lambda:self.suspend_as_reboot(self.wake_by_power_button)) 

I haven't looked at that test at all, but it depends if the DUT was suspended by closing the lid or just some `power_dbus_suspend` command. Ideally both should be tested. 

So it sounds like you want to extend suspend_as_reboot()?
Now it only suspends by powerd_dbus_suspend().
Would you like to add an argument called suspend_func() to support something like lid_switch_suspend()?

Yeah, that sounds good to me. Reading that test, I wonder why that tests for x86 only? It may just be an artifact of the past. I don't see anything immediately obvious why it would not work for ARM devices.

When I think deeper, I found this is actually weird.
If you suspend DUT by closing the lid switch, you cannot wake it up by pressing the power button since the lid switch is still closed.

+jwerner

The point of that is to support the docked case. (DUT plugged into external monitor, but with lid closed).