We propose a low-overhead method for delay fault testing in high-speed asynchronous pipelines. The key features of our work are: (i) testing strategies can be administered using low-speed testing equipment; (ii) testing is minimallyintrusive, i.e. very little testing hardware needs to be added; (iii) testing methods are extended to pipelines with forks and joins, which is an important first step to testing pipelines with arbitrary topologies; (iv) test pattern generation takes into account the likely event that one delay fault causes several bits of data to become corrupted; and (v) test generation can leverage existing stuck-at ATPG tools. In describing our testing strategy, we use examples of faults from three very different high-speed pipeline styles: MOUSETRAP, GasP, and high-capacity (HC) pipelines. In addition, we give an in-depth example"including test pattern generation" for both linear and non-linear MOUSETRAP pipelines.