There are no known works with the title Testing the Shaft.  The closest match in terms of theme, color palette and lighting intensity is a painting titled Jerry, with Apache Bow and Arrows that was first exhibited in 1921 at the Hotel Gibson galleries in Cincinnati at a show titled Indian Paintings. It was exhibited along with a larger, more complex work titled Making Sweet Grass Medicine that shares much of the tone and quietude of this canvas. (see related image, #244)