Currently the way that ICU uses unitsTest.txt, it assumes that source units convert from 1000 to the specified value in the base unit, and can then convert back. Bit for beaufort, the maximum scale value is 17, so a value of 1000 is treated as a7, then converted to a corresponding m/s value; converting tha back yields 17, not 1000.

Perhaps the test file needs an optional separate field for the result of the back conversion