In the event an error appears in regards to testing or if the screen appears to be mis-sized on a chromebook this article will walk you through the keyboard shortcut and manual method of resetting the resolution.
Keyboard Shortcut to set resolution
Control+Shift+0 (number 0 not letter)
Manual Settings
When logged in, Click on the time/account button in the bottom right of the screen
Click on the settingsbutton
Click on the Device option on the left
Click on Display
Scroll down to display size
Move the slider to 100% or "looks like 1366x768 (native)" This should be the second from the left on the slider
Your chromebook is now reset to it's default resolution and should be functional for testing and normal use.