The Speed Capabilities test will first check the speed of each interface that the device lists through ethtool. Then it compares each interface speed to a user-defined set of expected speeds set in a newly created config file, `speed_capabilities.cfg`. The test fails if an interface is found that isn’t accounted for in the cfg file, the detected speed is less than 1 Gb/s, or an interface detects a different speed than what is expected from the cfg file. Otherwise, it passes.