According to a statement from a company spokesperson given to Eater.com, "Sweet potato fries are being tested in some Create Your Taste test restaurants in Amarillo, and we're gathering valuable customer feedback on them."
Sweet potato fries tend to be more of a fast-casual side, which fits with McDonald's fast-casual-ish Create Your Taste concept. Still, McDonald's isn't exactly treading new ground here. Rivals Burger King, Jack in the Box, and Carl's Jr. have all sold sweet potatoes fries on a limited-time basis in the past (with Burger King also serving curly sweet potato fries at one point), while Sonic offered sweet potato versions of their signature Tots not too long ago. Wendy's even put a plain sweet potato on the menu back in 2012.
Photos via McDonald's.