Of the many steps in the process of assembling a wire harness, testing the crimped terminal is a crucial one. If the terminal hasn't been properly attached to the end of the wire, it can cause the wire and eventually the entire wire harness to fail. Most manufacturers use pull testing to assess crimped connections and ensure that terminals are properly attached.
Problems related to improper manufacturing, selection and installation are just as likely to cause fastener failure as hydrogen embrittlement and loosening
There are many ways to perform destructive testing. The most helpful, and preferred by manufacturers, is to intentionally destroy an assembly in a controlled environment to determine the performance capability of one or more of its components. Another way, done unintentionally and all too often by consumers, is to simply misuse a product.