Add some gfx tests

Unfortunately some of these tests are not rendering correctly, but I'd add them anyway and enable them when we fix them.
I'm not sure about the TextBox test, it may depend on timing (if it fails on travis, I'll try to fix it)
Nit: I might make this catch an InterruptedException specifically. And sleep for less time, like 100ms. Although ideally we'd register for some event that occurs when the TextBox is shown. There doesn't seem to be such an event, however.