Now that we're talking about floating point conveniences (math.nan, linspace): What about putting an almost_equal(x,y,tol=1e14) (or close(), or...) in the math module. AFAICT, in the standard library, there is only: unittest.TestCase.assertAlmostEqual but it: A) is buried in the unittest.TestCase class B) is an assertion, so you can't use it as a general test (easily) C) uses number of decimal digits or an absolute delta, but does not provide a significant figures comparison, which is most likely what's wanted (and a bit harder to write yourself) numpy provides allclose() (and isclose() ), which is pretty much what I'm suggesting. Anyone else think this would be a good idea to add to the stdlib? -Chris -- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception Chris.Barker@noaa.gov