A mutation testing tool takes as input a system under test and a test suite and produces as output the mutation score of the test suite. The tool systematically creates mutants by making small syntactic changes to the system under test and executes the test suite to determine which mutants give different results from the original system. Almost all mutation testing tools have been developed for statically typed languages. The lack of tools for dynamically typed languages may be rooted in additional challenges that are caused by the lack of precise type information until the program is executed. Existing tools for dynamically typed languages mostly focus on mutation of literals because the type of literals are known statically.

A new, low complexity method facilitates low burden embedding and recovery of tonal watermarks in speech. A watermark composed of a periodically extended sequence of sub-audible DTMF tones is added to speech asynchronously, without regard to momentary speech characteristics. It is detected through a combination of a bit manipulation enhancement and a data-directed correlation, ideal for simple hardware implementations. Three methods of bit manipulation enhancement were auditioned and the best selected for further investigation. It showed an average 26 dB processing gain vs. correlation alone, sufficient to detect the asynchronous sub-audible tones by a comfortable margin.