Demonstrates an android espresso bug related to TextInputLayout.setError
When an app calls TextInputLayout.setError after a button click in an espresso test the test code will hang indefinitely. I've tracked this down to Tap.java line 170 - if (!MotionEvents.sendUp(uiController, res.down)). The MotionEvents.sendDown prior to this line works fine, but MotionEvents.sendUp never returns.
Commenting out line 84 of MainActivity will cause the test to complete (but fail which would be expected). As written though the test hangs.