require 'facets/math/sign' test_case Math do class_method :sign do test do Math.sign(-3.1).assert == -1.0 Math.sign( 0.0).assert == 0.0 Math.sign( 3.1).assert == 1.0 end # Check complementarity of abs and sign #assert_equal_float(-2.0, Math.abs(-2.0) * Math.sign(-2.0), 1e-6) #assert_equal_float( 0.0, Math.abs( 0.0) * Math.sign( 0.0), 1e-6) #assert_equal_float( 3.0, Math.abs( 3.0) * Math.sign( 3.0), 1e-6) end end