A "ping test" is a simple network diagnostic tool used to check the connectivity between two devices over the internet or a local network. It sends small packets of data, called "ICMP echo requests," to a target device, such as a computer or a server, and measures the time it takes for the device to respond. This helps determine if the target is reachable and how quickly data can travel between the two points. Ping tests can also provide information about network performance, including packet loss and latency. High latency indicates delays in data transmission, while packet loss means some data packets did not reach their destination. Network administrators often use ping tests to troubleshoot connectivity issues and optimize network performance.